Here are strategies for each Pokémon family in the game, both for in-game and competitively. Note that in the strategies section, the sets are based off the final evolution, if their first stage can evolve in R/B/Y.
- 1 Bulbasaur, Ivysaur, and Venusaur
- 2 Charmander, Charmeleon, and Charizard
- 3 Squirtle, Wartortle, and Blastoise
- 4 Caterpie, Metapod, and Butterfree
- 5 Weedle, Kakuna, and Beedrill
- 6 Pidgey, Pidgeotto, and Pidgeot
- 7 Rattata and Raticate
- 8 Spearow and Fearow
- 9 Ekans and Arbok
- 10 Pikachu and Raichu
- 11 Sandshrew and Sandslash
- 12 Nidorans (males and females)
- 13 Clefairy and Clefable
- 14 Vulpix and Ninetales
- 15 Jigglypuff and Wigglytuff
- 16 Zubat and Golbat
- 17 Oddish, Gloom, and Vileplume
- 18 Paras and Parasect
- 19 Venonat and Venomoth
- 20 Diglett and Dugtrio
- 21 Meowth and Persian
- 22 Psyduck and Golduck
- 23 Mankey and Primeape
- 24 Growlithe and Arcanine
- 25 Poliwag, Poliwhirl, and Poliwrath
- 26 Abra, Kadabra, and Alakazam
- 27 Machop, Machoke, and Machamp
- 28 Bellsprout, Weepinbell, and Victreebel
- 29 Tentacool and Tentacruel
- 30 Geodude, Graveler, and Golem
- 31 Ponyta and Rapidash
- 32 Slowpoke and Slowbro
- 33 Magnemite and Magneton
- 34 Farfetch'd
- 35 Doduo and Dodrio
- 36 Seel and Dewgong
- 37 Grimer and Muk
- 38 Shellder and Cloyster
- 39 Gastly, Haunter, and Gengar
- 40 Onix
- 41 Drowzee and Hypno
- 42 Krabby and Kingler
- 43 Voltorb and Electrode
- 44 Exeggcute and Exeggutor
- 45 Cubone and Marowak
- 46 Hitmonlee
- 47 Hitmonchan
- 48 Lickitung
- 49 Koffing and Weezing
- 50 Rhyhorn and Rhydon
- 51 Chansey
- 52 Tangela
- 53 Kangaskhan
- 54 Horsea and Seadra
- 55 Goldeen and Seaking
- 56 Staryu and Starmie
- 57 Mr. Mime
- 58 Scyther
- 59 Jynx
- 60 Electabuzz
- 61 Magmar
- 62 Pinsir
- 63 Tauros
- 64 Magikarp and Gyarados
- 65 Lapras
- 66 Ditto
- 67 Eevee, Vaporeon, Jolteon, and Flareon
- 68 Porygon
- 69 Omanyte and Omastar
- 70 Kabuto and Kabutops
- 71 Aerodactyl
- 72 Snorlax
- 73 Articuno
- 74 Zapdos
- 75 Moltres
- 76 Dratini, Dragonair, and Dragonite
- 77 Mewtwo
Bulbasaur, Ivysaur, and Venusaur
Bulbasaur is both Grass- and Poison-type, but it really doesn't show much of its Poison side. Almost every decent Grass-type in the game has this type pairing, so it's not a matter of much concern. It specializes in the Special stat, which is ironic given that it has a lot of support-type moves like Leech Seed and Poison Powder. Bulbasaur, unfortunately, has few damaging attacks that aren't Grass-type, meaning that it can't really fight Flying-, Bug-, Fire-, Ice-, Poison, or other Grass-types effectively. It makes up for this by being effective against Water- and Rock-types, two types that are quite common and tend to be very annoying without super-effective moves. It also gets Razor Leaf, a move that always results in a critical hit once you reach Venusaur due to the way that mechanic works in this game, and can actually even hit things with a Grass resistance pretty hard. Probably the best choice for the beginning player, as it has an immunity to the Poison status (helpful in Viridian Forest), an advantage against the first few gyms, and is probably the best of the many Grass/Poison Pokemon in the game. Even Yellow players should consider adding one to the team in Cerulean City, if only to fight Misty with another super effective party member.
|Growl||1||1||1||-||Disable: lowers enemy attack||-|
|Leech seed||7||1||1||Grass||Healing: drains HP from enemy every turn||-|
|Vine whip||13||13||1||Grass +STAB||-||-|
|Poison powder||20||22||22||Poison||Disable: deals poison damage every turn||-|
|Razor leaf||27||30||30||Grass +STAB||-||High critical hit rate;
always critical for Venusaur
|Growth||34||38||43||-||Support: increases user's Special||-|
|Sleep powder||41||46||55||-||Disable: enemy falls asleep||-|
|Solar beam||48||54||65||Grass +STAB||-||It takes two turns|
- Razor Leaf
- PoisonPowder/Sleep Powder
- Mega Drain/Body Slam
This strategy is to deal a lot of damage and annoy others. Growth raises Venusaur's Special, and PoisonPowder or Sleep Powder annoys the opponent. Razor Leaf does lots of damage due to always getting a critical hit off of the move. Sleep Powder is probably better than PoisonPowder, however. This is because the foe can bring out an unexpected Gengar, but if you use Sleep Powder, for a while, you'll be fine. Mega Drain, while weak, can still help to restore health and would be more powerful when Growth is used. Body Slam gives Venusaur a Normal-type attack if needed.
- PoisonPowder/Sleep Powder
- Razor Leaf/SolarBeam/Mega Drain
This strategy annoys opponents with Toxic, Rest, PoisonPowder, and Sleep Powder. Once again, Growth raises SolarBeam/Mega Drain's power and strengthens its special so it can take less damage from other special attacks while Razor Leaf would always do critical hits. Basically, this is a set to keep Venusaur safe, annoy the opponent, and deal damage.
- Other Options
Since Venusaur gets Swords Dance, having that with Body Slam, Double-Edge, or Hyper Beam can help. Double Team can work nicely, and when used properly, Substitute can help out too. Other than that, however, there isn't much that Venusaur has that's actually helpful.
Charmander, Charmeleon, and Charizard
Charmander has the highest Speed of the starters, and it learns the powerful Fire-type attack Ember as early as Level 9. The problem with it is that it doesn't get a better Fire-type move until Level 46 as a Charizard, so Charmander hits a rut in the middle of the game as a Charmeleon, where it loses its effectiveness. It also has a disadvantage against the first two gyms, although it isn't particularly bad against the first. Charmander is the only Fire-type until right before your fourth badge, so it may be worth choosing just for that reason. And a word of advice to you if you do pick Charmander - don't use a Flying-type. It will steal experience from your lizard because it has advantages against the same opponents.
During much of the game, and even after learning more powerful Fire-type moves, Charizard will have to rely on non-Fire attacks. Fortunately, there are some good options here. Rage and Slash are learned by leveling up, and TMs and HMs can be used to teach Charizard Fly (Yellow only), Strength, and Earthquake. Ultimately, Charizard becomes as useful for its physical moveset as its Fire attacks, thanks to its decent stats all around.
- Flamethrower/Fire Blast
- Slash/Body Slam
- Fly (Yellow Only)
This is a full offensive set, with no moves that don't do damage. Slash/Body Slam is a good Normal move, and Earthquake/Dig are both good, depends if you want to attack right away or be protected one turn and then attack. Fly is a good Flying-type move and gives a Pokemon that can travel across the map with Fly but it's only in Yellow. Lastly, Flamethrower and/or Fire Blast are powerful STAB attacks, but it's your choice whether you want a strong but inaccurate move or a weaker but much more accurate one.
- Double Team
- Flamethrower/Fire Blast
- Body Slam
This set is used to keep Charizard safe. Fire and Normal type moves are used to help you when you've gotten defensive enough. Double Team is to prevent your opponent from hitting you. Lastly, it's your choice whether you want to lower your opponent's defense or raise your own.
- Other Options
Similar to Venusaur, Swords Dance can help you with Hyper Beam, Double-Edge, Mega Punch/Mega Kick, and other strong, physical moves. Charizard can use Swift if it needs to, and Strength isn't that bad if you need a Pokemon who can move boulders in Victory Road.
Squirtle, Wartortle, and Blastoise
Water-type Squirtle specializes in the Defense stat, but isn't really that low in the others. Its moves are a little on the weak side (and strangely not very defensive) until later in the game, but it's still more reliable than Charmander. The important thing to keep in mind before choosing Squirtle is that, unfortunately, there are equal and better Water-types later in the game, whereas Charmander and Bulbasaur are among the best in theirs. This doesn't mean that you can't choose Squirtle, it just means that you're giving up something like Cloyster or Vaporeon.
If you choose a Squirtle, you'll find that it works pretty well throughout the game. Water and Normal attacks flow in at a decent rate, culminating with HM moves like Surf and Strength. Ice moves can be taught via TM, and are useful against a variety of opponents.
- Surf/Hydro Pump
- Ice Beam/Blizzard
- Body Slam
This is an offensive set that provides Blastoise good coverage thanks to its wide movepool. Surf/Hydro Pump hits with STAB power, dealing a lot of damage, while Ice Beam/Blizzard does super effective damage against Grass-type Pokemon. Body Slam can be used as a above average powered Normal-type move. Earthquake is a Ground-type move that gives Blastoise a physical move to hit hard on Electric-type Pokemon while Reflect can be used to raise Blastoise and it's team's defense.
- Double Team
Blastoise also has useful options for playing defensively. Reflect raises its defense while Double Team helps to raise its evasion. While it takes 25% of its health, Substitute can be used to safely protect Blastoise from weak attacks while Toxic can be used to badly poison opponents while using Double Team and/or Substitute to annoy them due to not letting them attack it, as they slowly lose HP from poison. Surf can be used as an attacking move if needed.
- Other Options
Hyper Beam, Double-Edge, and Mega Kick can be alternatively used as more powerful Normal-type moves in place of Body Slam. Fissure can also be learned by Blastoise and can effectively dispatch teams with the use of a X Speed and a X Accuracy.
Caterpie, Metapod, and Butterfree
If you invest enough time in Caterpie, it will end up as a Bug- and Flying-type Butterfree that can gain status causing moves such as Stun Spore and Sleep Powder, as well as a basic Psychic attack in Confusion (this is a damage attack). Butterfree can be extremely helpful in the early portion of the game. However, Butterfree is quickly out-classed by other Pokémon such as Bellsprout and Oddish as a status-inflicter, and Kadabra and Hypno in terms of Psychic power. It gets its moves earlier in Yellow, and even learns a new one, but it's still not much of a late-game Pokémon.
Butterfree works well with a moveset of Confusion, Sleep Powder, and any combination of Supersonic, Stun Spore, and Poison Powder. If, for some reason, you choose to keep using your Butterfree into the latter portion of the game, then Confusion can be replaced by Psybeam or even Psychic, although the latter is a TM that may only be used once. Mega Drain is a decent attack as well, and most Grass-types don't particularly need it.
Weedle, Kakuna, and Beedrill
Weedle doesn't start out much differently than Caterpie. It's pretty weak when you get it, and evolving it into Kakuna doesn't make things much better. But Weedle's evolution continues at a lightning pace, and at level 10 you'll have a very useful (at least for the early part of the game) Beedrill. Beedrill learns the best Bug-type attack, Twineedle, at level 20, but Beedrill's Poison-type and low stats make it pointless as an anti-Psychic Pokémon. That said, it should do well fighting Grass and other Poison types. Ultimately, Beedrill is fairly weak, only able to keep up with opponents until around Rock Tunnel, where you may want to consider finding a replacement.
Beedrill doesn't really have much going for it in the way of attacks. Avoid the useless Rage (takes several turns to start doing damage) and Focus Energy (glitched; lowers critical hit rate instead of increaing it). Twineedle is a must, being the best Bug-type attack in the game, and Pin Missile is decent as well. If you wish to keep your Beedrill even after it's outlived its usefulness, then Mega Drain is a good move that allows it to hit Rock-types effectively.
Pidgey, Pidgeotto, and Pidgeot
Pidgey is probably the single most common Pokémon in the game, so it's not like you'll be looking for opportunities to catch one. They're not exceptional, but their Flying-type status has an advantage over Grass- and Bug-types. Also, Ground-type moves will not affect Flying-types. Unfortunately, Pidgey doesn't learn much in the way of flying attacks, learning only a single weak one by level-up, so you'll have to just think of it as a Normal-type for now. Spearow is likely a better choice for a Flying-type. But there is one decent strategy you can use with Pidgey: Sand-Attack, which Pidgey learns at Level 5, will decrease enemy accuracy enough after a few uses to completely prevent your opponent from attacking! Just keep in mind that Pidgey still needs to be properly leveled to execute this or it will be knocked out before it can finish. Pidgey's okay for the beginning of the game, and it gets better towards the end. Bear in mind though, that other Pokemon can perform a similar role.
If you use a Pidgeot, be sure to take advantage of its typing. Gust should be replaced by Quick Attack and Wing Attack should be replaced by Fly ASAP. After that, Pidgeot relies heavily on tricks and TMs. Agility can raise its already decent Speed to maximum levels, TMs, like Swift, Take Down, and Double Edge, can give it a powerful Normal attack, and the naturally learned Mirror Move can be used to turn an opponent's moves against them. Whirlwind is useless in trainer fights, and considering how you can simply run from most battles, should be avoided.
Rattata and Raticate
Not the sturdiest of Pokémon, but Rattata can learn the awesome 80 base power Hyper Fang at a mere level 14, which is enhanced by the type-matching bonus. At level 20, Rattata evolves into the stronger Raticate. Much later on, it can learn Super Fang to help in efforts to weaken a target Pokémon for capture; it will cut the target's current HP in half with each use. Rattata makes a great choice for the early portion of the game, learning a couple of good TMs and being able to handle almost any Pokémon once it learns Hyper Fang. Even so, Rattata is not a good team member for getting through the entire game: You may want to leave it in the PC around the time you defeat Erika, later in the game.
If you use a Rattata/Raticate, there are two essential moves: Hyper and Super Fang. Hyper Fang is very powerful in the early game and should be kept until you teach the only slightly better Body Slam or another similar move via TM. If these moves are not available, Hyper Fang is still a viable option in the late game. Super Fang, on the other hand, should always remain a part of Raticate's arsenal, due to its sheer usefulness, especially against powerful opponents that Raticate can survive a hit from. Besides that, Raticate should learn some TM moves, if only to fill up the slots that its small natural movepool doesn't. Dig works well against Lt. Surge, Ice Beam does wonders against Erika, and electric attacks do well against many opponents.
Spearow and Fearow
Spearow may not have a third stage of evolution like Pidgey do, but they're actually a bit stronger, and a bit rarer early on. Unlike Pidgey, Spearow begins with a Flying attack in Peck, and is destined to learn what is probably the best one: Drill Peck. Spearow has an immunity to Ground-type attacks, as well as dealing increased damage to Grass-, Bug-, and Fighting-type opponents. The increased damage against Bug-types will help a lot as you make your way through Viridian Forest.
Fearow's chief attack will be Drill Peck, probably the best Flying type move for actual use in game. Later on in the game, he works well using powerful Normal TMs like Hyper Beam and Double Edge. Mirror Move also allows for some interesting possibilities in battle.
Ekans and Arbok
Ekans is interesting because it comes with Wrap. Use Wrap repeatedly against slower enemies to choke the life out of them while preventing them from ever getting an attack in. On the downside, Ekans doesn't really learn anything particularly interesting as it grows and evolves into Arbok, which is not inherently powerful by itself. Ekans is not a particularly good Pokémon, but not a bad one by any means.
If you want to use an Arbok, make sure it learns Glare, a Paralyzing move with 75% accuracy. Keep Wrap for as long as possible; it is a major irritant to enemies, even without a lot of power behind it. If you're the irritant type of trainer, make sure you also teach it Toxic so Wrap is even more effective. If you want to use TMs, Body Slam and Earthquake take advantage of Arbok's higher attack, although admittedly not its typing. Mega Drain, while not particularly strong due to Arbok's low Special stat, is still strong enough to help it take on Rock-types if you don't want to use your Earthquake TM on it.
Pikachu and Raichu
Pikachu is perhaps the most popular and recognizable Pokémon in the franchise although it isn't much of a tough fighter. Yellow players are always given a Pikachu by Prof. Oak as their starter. This is a bit disappointing from a statistical standpoint, as Pikachu's only good stat is Speed. It makes up for it by being an Electric-type, one of the best all-around types in the game. While it makes Pikachu weak against Ground-type attacks and they can OHKO it easily due to its pathetic defenses, Electric attacks absolutely shred the game's plentiful Flying- and Water-types. You can see this at work as Pikachu's Thundershock fries the Pidgeys hanging around Route #1. Unfortunately, Pikachu can't evolve in Yellow, so it can have a hard time against tough opponents.
Pikachu is quite different in Red and Blue than in Yellow. It lacks Thunderbolt by level-up, so you'll have to use a TM in Vermilion City. It gets Swift, but at the expense of better moves such as Double Team, Slam, and even Light Screen later on. The big advantage is that Red and Blue Pikachu can evolve into Raichu, giving it good attacking stats and making it much stronger in the long run. Definitely a good Pokémon to pick up, particularly if you chose Bulbasaur and need a Flying-type counter.
- Standard Offensive
- Body Slam
- Thunder Wave
Raichu/Yellow Pikachu are the only Electric-type Pokémon that are not walled by Rock/Ground-types such as Rhydon and Golem, thanks to Surf from learning it from Pokémon Stadium. STAB Thunderbolt would be its main attack, while Body Slam would be its Normal-type attack to attack physically. Thunder Wave is used to inflict paralysis, slowing targets down.
- Thunder Wave
- Double Team
- Light Screen (Yellow only)/Reflect/Body Slam/Surf
Not so much as an offensive but this set can be very annoying to many opponents. Like the previous set, Raichu/Yellow Pikachu uses Thunder Wave on opponents, use Double Team to increase you evasion, and rain STAB Thunderbolts on the crippled opponents who's attacks are missing you. The fourth slot can vary, with Reflect/Light Screen raising your defense on Physical and Special attacks respectively in case if they do hit Raichu/Yellow Pikachu, while Body Slam/Surf gives an attacking option so you aren't totally walled by Grass and Ground-types.
- Other options
The above sets mostly got Raichu/Yellow Pikachu covered already but Submission can give it a Fighting attack they can use on Normal-type Pokémon like Chansey who can wall its Special attacks. Hyper Beam is a much more powerful alternative for Body Slam but do mind that if it doesn't finish a target with it, it can risk a charging delay turn.
Sandshrew and Sandslash
This Ground-type Pokémon doesn't learn anything particularly exciting on its own (Although it does get the powerful Slash attack at a fairly low level). It has good Attack and Defense (especially in its final form), although it doesn't have much Special or Speed. The lack of a Rock-type means that it can potentially survive a medium power Grass- or Water-type attack if it must take one. While it must use a TM to give it a Ground attack (Like Dig, which you'll get at Cerulean City), Sandshrew is a great Pokémon that is pretty useful throughout the game.
As mentioned above, Sandslash requires a TM to use any STAB moves, so save Dig and/or Earthquake. On its own, Sandslash learns the powerful Slash attack, which works fairly well late into the game. Alternatively, you can use TMs to teach it Swords Dance and a move like Strength or Body Slam, since Slash doesn't work well with Swords Dance in this game. Sand-Attack, although a very basic move, is valuable throughout the game. Also consider teaching Rock Slide to counter Ice and Flying types.
Nidorans (males and females)
Female Nidoran, Nidorina, and Nidoqueen
Female Nidoran are everywhere in Blue, and males abound in Red, but both appear with equal frequency in Yellow. Yellow gives them both Double-Kick at level 12, useful against the many Rock- and Normal-types that are everywhere early on. While the female form is Poison-type, it doesn't get a lot of Poison moves - Poison Sting is about it. It makes up for it by learning practically every good TM in its final form. Both Nidoran can reach their final forms through the use of a Moon Stone.
Nidoqueen is functionally similar to Nidoking, albeit with higher defenses and lower offense. Like Nidoking, it relies heavily on TMs for learning good moves. Try teaching it Surf, Blizzard, Thunder, Earthquake, Strength, or maybe Horn Drill.
Male Nidoran, Nidorino, and Nidoking
The sharper horned male Nidoran have a slight edge over the females, since they learn better offensive attacks in this and the next phase of their evolution (as well as having a better Attack stat to use it with), but both are solid all-around fighters throughout the game. Yellow gives them both Double-Kick at level 12, useful against many opponents in the early game. While a Poison-types, it only really gets one Poison attack - Poison Sting, which isn't really any good even when you first get it. On the other hand, Nidoran learns pretty much every good TM in its final form. Both Nidoran can reach their final forms through the use of a Moon Stone. Either Nidoran makes a great team member, able to cover a wide variety of foes.
Nidoking is best used as a user of both Physical and Special moves. Many of these require TMs, so hopefully you've been saving them up. Try teaching Earthquake at the very least, in order to have a solid move that gets STAB from Nidoking's Ground typing. The rest of the moves can be filled by Double Kick or Thrash (Level-up), as well as Blizzard, Thunder, Body Slam, Strength, Surf, Ice Beam, or Rock Slide (TM).
Clefairy and Clefable
Clefairy and Jigglypuff are very similar; both are pink, puffy Pokémon that evolve with a Moon Stone, have a ton of HP, and can use just about any TM. However, Clefairy has much better stats overall. Clefairy isn't very useful with only its level-up moves, but can learn a wide variety of helpful TMs. Clefairy is definitely better than Jigglypuff, and you'll find the TM for Water Gun right around the same time in Mt. Moon, making it useful for dealing with Geodudes in that part of the game.
The nice thing about Clefable is that you can shape it into whatever you want. If you need a physical fighter, try teaching it powerful Normal moves like Hyper Beam, Strength, and Mega Kick. If you need a Special fighter, give it TMs for Fire Blast, Blizzard, and Thunder. If you need a status inflicter, it can learn Toxic, Thunder Wave, and Sing. It may not be the best at any of these things, but it can fill pretty much any hole in your party..
Vulpix and Ninetales
The many-tailed firefox Vulpix, like Growlithe, evolves into its final form with the aid of a Fire Stone. Vulpixes may not be as tough as Growlithes, but they are a bit quicker, and they learn their best skill (Fire Spin, the Fire version of Wrap) as soon as level 42. Use the Stone then and you'll have a tough and versatile, good all around Ninetales.
Try teaching Ninetales Fire Blast to accompany Fire Spin. Confuse Ray is great all game, and should also be learned and kept. The last moveslot should be filled by anther non-Fire attack, possibly Swift, Double Edge, or Body Slam.
Jigglypuff and Wigglytuff
Jigglypuff, even more ridiculously cute in Yellow, have a ton of HP, but are mediocre in all their other stats. Pound works well enough early on, but Jigglypuff will be starved for good attacks until it learns Body Slam at level 34. Jigglypuff can use a wide variety of powerful TMs, but it probably isn't worthy of these precious TMs, as the result isn't spectacular. Jigglypuff can evolve right away with a Moon Stone, found in Mt. Moon, but this will keep it from learning moves through leveling up.
Jigglypuff should definitely not be evolved until at least level 34, when it learns Body Slam. This move will drive Pound and DoubleSlap obsolete, and is arguably better than Double-Edge and Strength. Sing attack is annoying to be put to sleep by, but is nearly a coin-flip in accuracy. Useful TMs include Thunder Wave, Hyper Beam, Bubblebeam, Flash, and Counter.
Zubat and Golbat
Zubat isn't that good. It's a Poison and Flying-type (although it doesn't learn any Poison attacks), so it's weak to many types. Leech Life's draining ability is useful, but is extremely weak at 15 power. It's hard to damage most things with it. Even when it eventually learns more attacks, such as Bite and Wing Attack, they simply aren't very powerful.
If you wish to use Golbat, there are a few redeeming features. Confuse Ray has a 100% chance of confusing a target Pokemon, making it an essential part of its moveset. However, this is not even a signature move, as several other Pokemon in the game can learn it. Bite works well until you can afford Hyper Beam, and Mega Drain works well against what Normal attacks can't. However, the lack of any powerful Poison or Flying type moves cripples Golbat, relegating it to nuisance territory.
Oddish, Gloom, and Vileplume
Don't worry if you're playing Red: there may not be any Bellsprouts, but you can still get a decent Grass-type by catching an Oddish. You'll need a Leaf Stone to reach the final stage of evolution, but keep in mind that it learns powerful moves like Petal Dance and Solarbeam later on.
Oddish's initial Absorb skill puts Leech Life to shame, and since it's Grass-type, one Oddish can take down dozens of Water, Rock or Ground-type Pokémon, healing as it goes. If you enjoy this strategy, be sure to save the TM for Mega Drain, which is the same thing with twice the power. Soon, Oddish will learn the standard array of status-inducing moves, before evolving into a Gloom. Before evolving Gloom, you will want to consider teaching Petal Dance and SolarBeam, but only if you don't teach Mega Drain. Consider teaching your fully evolved Vileplume moves like Body Slam, Cut, or Take Down to deal Normal damage and Acid to deal Poison damage and lower Defense.
Paras and Parasect
A unique Bug/Grass combo, Paras is very weak in general. Many claim it's a "Psychic stopper", given its Bug-type, lack of a Poison-type, and its Leech Life Bug-type attack. Unfortunately, this just isn't the case. Leech Life is extremely weak no matter what, and Paras' stats are mediocre. Paras' only saving grace is Spore, a Sleep-inducing attack with perfect accuracy that is great for catching Pokémon. Unfortunately, since Paras (more likely Parasect) is so slow, it will likely lose most of its HP before hitting anything with it.
If you use a Parasect, it MUST know Spore; otherwise, there isn't much of a point. Beyond that, Paras and Parasect have a limited array of moves. Slash works well, and should be kept unless you plan on using a replacement TM such as Body Slam. Beyond that, the most useful moves Parasect learns are Stun Spore and Growth. Growth, however, needs a Special type move to be used well, something that Parasect doesn't learn on its own. Try teaching the TM for Mega Drain; it works well with both Growth and Parasect's typing, and takes advantage of one of Parasect's better stats, its Special. Even Leech Life can see some real use when you take on Sabrina using a Parasect, as not only does it take advantage of both Psychic's weakness against Bug-type attacks and STAB, the massive (by that attack's standards) damage it can do there can help Parasect recover from any powerful Psychic-type attack even her Alakazam may inflict, and it's especially effective when paired with Spore.
Venonat and Venomoth
Available early in the game in Yellow only, Venonats are quite rare, but are hardly worth the trouble. It's just another Bug/Poison thing, albeit one that can learn good Psychic moves later in the game.
Venomoth is best used as a sort of variant of Butterfree, with a mix of status inducing moves and Psychic attacks. Most notable is its pretty good Speed, which makes it the fastest Sleep-inducing Pokemon in the game thanks to Sleep Powder. It can also use Stun Spore and Poison Powder if that's what you prefer. Venonat/Venomoth also learn Confusion (in Yellow only), Psybeam, and Psychic naturally, which should be its core offensive move. Other possibilities, via TM, include Mega Drain, SolarBeam, Toxic, and Psywave, a move that does a semi-fixed amount of damage.
Diglett and Dugtrio
Diglett and its evolved form Dugtrio are among the best Pokémon in the game. They're fast, get both Dig and Earthquake by level-up, and have the offensive stats to use them. Plus, they can learn other useful moves like Cut and Slash, in case you come across something Ground-type moves alone can't deal with. Sand Attack is also an option, thanks to its universal ability to lower accuracy. Probably the best Ground-type choice in the game (particularly in Red, where there are no Sandshrew.)
Meowth and Persian
Meowths are similar to (but not quite as good as) Rattatas: speedy with lots of Normal-type attacking moves. But there's one twist: at level 17, Meowth learns Pay Day, a solid attack that pays you back money equal to double Meowth's level each time it's used. If you find yourself frequently short on cash, it could come in handy. Meowth's evolved form Persian is a common competitive choice, so you may want to raise one. It has little use in-game, however.
If you're using a Meowth or Persian in-game, you'll find that Pay Day is one of the best ways to gather spare cash after you've beaten trainers in an area. Beyond that, Persian still has a number of options. It should start with Scratch as a Meowth, pick up Bite to replace it before evolving, and eventually will learn Fury Swipes and Slash, a pair of solid Normal moves. Slash is recommended if only for its accuracy, but considering how late Persian learns it (Level 51), it might be worth investing in another move in the meantime. Fortunately, Persian can also learn moves like Body Slam, Take Down, Swift, and Double Edge via TM, although it lacks the convenient Strength. Beyond these basic Normal moves, Persian should also remember Screech to cut enemy defenses in half. As for the rest of the move slots, consider teaching Bubblebeam, Thunderbolt, and Hyper Beam via TM.
Psyduck and Golduck
Red and Blue players can fish up one of these Water-type Pokémon if they really want to. Psyducks start with nothing in the way of particularly useful attacks and don't get good stuff like Fury Swipes and Hydro Pump until much later. They can do some damage with Surf, but their stats are just too low, even after evolving into Golduck.
The good news is, a fully fledged Golduck isn't a bad fighter. It can learn some useful Normal, Water, and Ice moves, via leveling up and TMs, and even learns Confusion along the way, a useful move for a growing Water Pokemon. It's just that there are so many Water Pokemon out there, it's hard to recommend this one over the others.
Mankey and Primeape
Only available early on in Yellow, you'll find Mankey's Low Kick to be very useful against Normal- and Rock-types. In Yellow, it learns Low Kick at an easy level 9. It's first available on Route 5 in Red and Blue, but it isn't really worth it in those games: it can't learn Low Kick, so its only Fighting-type attack is the fixed damage Seismic Toss.
If your Primeape can't learn Low Kick, at very least teach it Submission via TM. Beyond that, Mankey and Primeape have a few choices. One thing that isn't lacking in this family are good Normal moves, starting with the weak Scratch and culminating in Karate Chop, Fury Swipes, and Thrash. Even better, Primeape can learn moves like Body Slam and Strength via TMs and HM04. Teaching Rock Slide is another good idea, since it counters both Ice and Flying Pokemon, covering whatever Fighting and Normal moves don't. Beyond that, consider teaching Screech to lower enemy defenses, Dig to deal with Electric and Fire Pokemon, and Mega Kick for maximum Normal damage.
Growlithe and Arcanine
Growlithe's a tough fighter with decent Fire attacks, who turns into one of Red's toughest brawlers when you power him up (into Arcanine) with a Fire Stone. But you may want to wait on that until he learns his best technique, Flamethrower, at level 50. Even then, relying solely on Flamethrower might not be the best idea; though Arcanine has good Special, its physical Attack is even better. If you make one into a main party member, try teaching it at least one physical move, like Hyper Beam or Body Slam.
Poliwag, Poliwhirl, and Poliwrath
Water-type Poliwags evolve two times: into Poliwhirl at level 25 and into Poliwrath with the aid of a Water Stone. At that third stage of evolution, they gain Fighting-type characteristics, but once again, their inability to learn any Fighting-type techniques makes this more of a liability than an asset. Certainly not one of the better Water-types.
If you choose to use a Poliwag, you might want to wait a while before using a Water Stone; Poliwhirl learns Body Slam at level 33 and Amnesia at 41. Once fully evolved, you'll find that despite its unfortunate typing, Poliwrath is surprisingly bulky for a Water Pokemon, and although more of a Physical beast, has enough Special to use Water attacks. Hence, both Body Slam and Surf are great moves to teach. However, things can get even better. Amnesia is overpowered in RBY, meaning that Poliwrath's Surf can be made into a powerful force. Meanwhile, if you still have the TM for Submission, this makes up for Poliwrath's inability to learn Fighting moves naturally, giving it a second powerful STAB move. Also consider teaching or keeping Hypnosis, Blizzard, Hydro Pump, and Counter.
Abra, Kadabra, and Alakazam
Abra can be difficult to catch. The only move they know is Teleport, which removes them from battle instantly. So if you're lucky enough to see one in the wild, you've got one turn to snag it. You have a few options: one is to have a Jigglypuff or Clefairy Sing it to sleep, or Sleep Powder if you have Butterfree, which makes it easier to catch and also gives you an opportunity to knock it around a bit while it's dozing. The next is to use Wrap to squeeze it until it's weak enough to catch, while keeping it from Teleporting away. The last option is to use Pikachu's Thunder Wave to paralyze it and capture it right away with a Pokéball (though this option isn't very reliable).
But are they worth it? Definitely, since Psychic Pokémon are the best in the game, and Abra evolves into the best one you can get (before the game ends, that is.) At level 16, Abra will turn into a Kadabra, which you can (and should) immediately trade to a friend to evolve it into a powerful Alakazam. Even if you don't, however, the Confusion attack Kadabra learns, combined with the Same-Type Attack Bonus it gives, grants even a level 16 Kadabra the ability to knock out almost any Pokémon of comparable level in one hit, even without type advantage.
Alakazam shines particularly in the late game, once it learns moves like Recover and Psychic. With Recover and its great Special stat, it is all but immune to Special attacks, and its powerful Psychic will dispatch of all but a small handful of Pokemon. Its movepool is limited, but with such a great strategy, it doesn't really need much else.
Machop, Machoke, and Machamp
They're not a common sight in any version, but anyone can track down and capture a Machop with a bit of effort. Machops are strong in Attack and HP and only get stronger as they evolve: into Machoke at level 26, and then into Machamp once they're traded. Hitmonlee is arguably a better option, especially if you can't trade, but Machop is available earlier.
Machamp may not be particularly fast, but it is great at dealing physical damage. Keep Low Kick until Submission comes along; you'll need one or the other to take advantage of this family. Karate Chop is a fine move, but Strength or Body Slam are even better if you have the HM or can spare the TM. Seismic Toss deals a set amount of damage, making it good for bypassing high Defense or Special stats. For your last move, consider Hyper Beam, Earthquake, Rock Slide, and Counter.
Bellsprout, Weepinbell, and Victreebel
Bellsprout are a good choice if you didn't pick a Bulbasaur early on and you need a Grass-type.
Bellsprout can thoroughly thrash your opponents early in the game, since they get the Wrap skill at level 13 and have the Geodude-beating Grass skill Vine Whip built right in. Their next couple of skills are all Poison, Sleep, and Stun moves. Sleep Power and Stun Spore are both useful for helping you catch and battle Pokémon. Later, they can replace Vine Whip with Razor Leaf, and can also be taught one of several Normal moves via Tm or HM. Victreebel's final moves should include Razor Leaf, at least one status-inducing move, and a Normal move.
Tentacool and Tentacruel
Tentacool mixes Water with Poison-types, and learns a variety of good attacks in both (and has a high enough Special to make good use of them). Built-in Poison attack Acid does damage while lowering Defense, which is nice, but Poison-types still aren't stellar.
Tentacruel is most notable as a Special Pokemon with good Speed. Be sure to teach it Surf, as with most Water Pokemon. It also naturally learns Wrap, a move that is viable throughout the game as a nuisance to opponents. Teaching Swords Dance via TM will increase Wrap's power while powering up other potential moves like Hyper Beam and Double-Edge. Screech can also be taught for the same purpose. Also consider teaching Tentacruel Ice moves and Mega Drain.
Geodude, Graveler, and Golem
Geodude is painfully slow, and its double weaknesses to Grass and Water can be devastating. However, its Attack and Defense can grow to high levels, especially as a Golem, and it can gain Rock and Ground attacks without the use of TMs. Geodude's strength against Electric, Flying, Fire and Normal attacks is also very useful throughout the game.
Key moves for the Geodude family include the Ground type Dig and Earthquake, which can decimate foes, the Rock type Rock Slide, which will crush Flying and Ice Pokemon, and Normal moves like Take Down, Body Slam, Strength, and Explosion. Just be sure to never teach it a move that relies on having a decent Special stat, as even Golem's Special is terrible.
Ponyta and Rapidash
Ponyta doesn't get the greatest skills... For Fire, it's just Ember for starters and Fire Spin at level 39. But the saving grace of Ponyta and its evolved form, Rapidash, is their incredible Speed, making them easily the fastest of the Fire Pokémon.
Ponyta should start with Ember and Stomp, a decent pair of moves. Fire Spin isn't learned too late either, at level 39. Besides that, Rapidash learns Take Down, which could replace Stomp, and Agility, which will make it the fastest Pokemon in any battle thanks to its already high Speed. Although Agility and Fire Spin can take care of most of Rapidash's opponents, there are some TM moves that can be useful. Stomp/Take Down can be replaced by Body Slam or Double Edge, and Fire Blast provides more sheer power than any other Fire move. Horn Drill also can be taught if you're a risky kind of player.
Slowpoke and Slowbro
Water and Psychic makes for a weird combo, but Slowpoke (and its evolved form Slowbro) learns some strong techniques in both, and have good enough stats to make good use of them. Most notably, Slowbro is the best user of Amnesia, which is monstrous in Red and Blue because it gives a simultaneous, and tremendous boost to Slowbro's offensive and defensive abilities!
As mentioned above, should definitely learn Amnesia; it literally doubles Special power. However, that's just one move. Slowpoke naturally learns Headbutt, which is a good choice until you can teach Strength, which takes advantage of Slowbro's decent Attack. Psychic is learned naturally, while Surf should replace Water Gun at earliest convenience. Besides these moves, Slowbro has several options. Blizzard is powerful when combined with Amnesia, Rest works well against most opponents thanks to Amnesia and Slowbro's natural Defense, and even Earthquake can be used to throw an opponent off guard.
Magnemite and Magneton
The Magnemites available early on in Yellow aren't as fast as their Voltorb cousins in Red/Blue, but their mix of strong Electric moves and Normal attacks is more versatile than Voltorb's Normal ones. They would be a good option, but you've already got Pikachu. If, however, you wish to not use Pikachu for some reason, then this is a good second choice.
Thunder or Thunderbolt is a must-have for Magneton, and should be the focus of any strategy involving it. Sonicboom is a great move early on, but should be replaced by the late game. Thunder Wave is very useful, compensating for Magneton's mediocre speed and possibly preventing attacks. Reflect, Screech, and Flash give it stat advantages, which can be taken advantage of using the naturally learned Swift or the more powerful Take Down, Double Edge, or Hyper Beam.
Farfetch'd, a ninja duck that beats its enemies with a giant leek, is pretty pathetic in battle. Farfetch'd has access to Swords Dance and the 100% critical hit Slash, as well as boosted experience due to being traded. None of those strengths overcome its terrible stats. More importantly, Farfetch'd learns both Cut and Fly, making it extremely useful in moving around the map.
If you absolutely must use Farfetch'd in battle, you have several choices. First, make sure it knows Fly to deal Flying-type damage and Slash to deal Normal damage. Swords Dance can help compensate for its low attack stat, while Sand Attack can give it some breathing room.
Doduo and Dodrio
Doduo, which can be caught in any version, is by no means terrible. In fact, it is probably the best of the Normal/Flying Pokemon. Drill Peck is a strong attack that's great against Fighting-type Pokémon (as well as more seldom-seen Grass and Bug Pokémon), but there's not a whole lot else to get excited about. The evolved form, Dodrio, which can be caught in Route #17 in Yellow only (or raised at level 31 in any version) is a fairly speedy, strong attacker that can do good damage with Normal skills like Tri Attack.
Ultimately, Dodrio is probably the best of the several Normal/Flying Pokemon in the game. However, by the time you get it, you'll start having to think about incorporating even more powerful Flying Pokemon into your party, such as the Legendary Birds. That said, if you want a speedy Pokemon that can deal plenty of physical hurt, Dodrio is a solid choice.
Seel and Dewgong
While it has a lot of competition, Dewgong's boosts to Water and Ice-type attacks give it an advantage over Blastoise and Articuno, and it hits significantly harder than Cloyster as well. Access to Horn Drill secures Dewgong's place as one of the best in-game Pokemon in Red, Blue and Yellow. That said, its options are a bit limited; Dewgong simply has less move choices than its competitors.
Grimer and Muk
Grimers (and the evolved Muk) are literally garbage. Well, maybe that's a bit harsh. They get a high Attack score and decent HP. It's just that Poison-types are the worst in the game, in that no Poison skill (except for maybe Toxic, which you have to use a TM to teach him) is good against the quickly-defeated computer opponents. If, for some reason, you decide that you need a powerful Poison Pokemon later in the game, it's not the worst choice.
Muk must learn Sludge to be useful. It's the game's best Poison attack, and incidentally the best STAB move Muk gets. Besides that, teach at least one more Physical move. Body Slam is ideal, but Explosion and Hyper Beam will do in a pinch. Also teach Muk Acid Armor and/or Screech to give it superior physical stats. Other good moves to teach include Disable, Mega Drain, and Thunderbolt.
Shellder and Cloyster
Like Poliwags, Shellders evolve into their higher form, Cloyster with the aid of a Water Stone. And like Poliwags, they gain a new type in the process: Ice. But very much unlike Poliwags, Shellders are worth using. They're incredibly strong on Defense and have a high enough Special to make use of their powerful Water and Ice attacks. Just don't use that Water Stone until at least level 30, when it learns Aurora Beam, or better yet, level 50 for the mighty Ice Beam.
Cloyster relies on Ice attacks, either Ice Beam or Blizzard, and Surf for Water damage. Anything that this doesn't annihilate can be taken out by Hyper Beam and Explosion. If you need a bit of variety, try using Clamp, essentially a Water-flavored variant of Wrap.
Gastly, Haunter, and Gengar
Gastlys are incredible! Not only are they immune to Normal and Fighting attacks, but they can learn both parts of the Hypnosis/Dream Eater combo by level 35. They're weak to Psychic and Ground attacks, but their immunities more than make up for that minor inconvenience. Built-in attack Night Shade does damage equal to Gastly's level regardless of type, and Lick paralyzes foes. And as they evolve, first by leveling up and then by trading, they gain some powerful stats. A full-fledged Gengar is a match to all but powerful Ground and Psychic Pokemon.
Once fully evolved, Gengar has quite a few choices. It is the fastest sleep-inducing Pokemon in the game, which works well combined with Dream Eater. Thunderbolt and Mega Drain don't receive any STAB, but Gengar makes up for it with his high Special. And in the late game, he even can be taught Explosion via TM.
Onix is a decent Rock-type Pokémon to have. It has exceptional Defense and decent Speed, but rather poor HP, Attack, and Special Defense, making it rather susceptible to Water attacks. It suffers from a lack of good move choices, but it takes physical hits well. Keep in mind, however, that despite its less impressive stature, Geodude's fully evolved stats and movepool are superior.
Onix should be taught Rock Slide and Earthquake if at all possible. Beyond that, Screech is a great way to compensate for its low Attack. Strength provides an extra offensive option, as do Bind and Explosion.
Drowzee and Hypno
Drowzees are great. They're reasonably sturdy and their Special is very high. They get Psychic (the game's best Psychic-type attack) naturally, along with a couple of status moves, and they really don't need much else. And even if you do want something else, they have Headbutt to inflict moderate physical damage with, compatibility with plenty of TMs, and even have enough bulk to consider Rest. The problem is that Kadabra (and especially Alakazam) has even better Special and has much better Speed. The choice is yours - fast striker or sturdy support Pokémon?
Krabby and Kingler
Krabby is a fairly good Water Pokémon, and you can have fun beating things instantly (30% of the time) with his Guillotine technique. But Krabby's real selling point is that he can learn Cut, Surf and Strength HM's, allowing you to have them all without using more than one slot on your bench.
In battle, Kingler is best viewed as a physical variant of traditional Water Pokemon. His signature move, Crabhammer, lacks the accuracy of Surf, but makes up for it with a high Critical rate, making it a fair alternative if you already have a Surfer. Beyond that, Strength works well with its high Attack stat. So does Hyper Beam, especially when paired with Swords Dance. Beyond that, Guillotine has a 1/3 chance of KOing an opponent.
Voltorb and Electrode
Voltorb look bizarrely similar to Poké Balls. Despite being Electric-type Pokémon, they learn no Electric attacks without the aid of TMs. Instead, they learn Normal attacks, including the self-sacrificing Selfdestruct. Once learned, this move should only be used in an emergency. Probably the worst Electric-type in the game, although its evolved form is the fastest of any Pokémon.
If you use a Voltorb or Electrode, teaching it an Electric move via TM is a must. Selfdestruct and Explosion are so powerful, they should be included in any moveset outside of a Nuzlocke run. Also consider using Screech, Flash, and Thunder Wave.
Exeggcute and Exeggutor
Exeggcute evolves into the powerful Exeggutor, who has high stats and great resistances, including the rare Ground one. In competitive gaming, Exeggutor is regarded as a staple in most teams due to it being a reliable sleeper and the number one Ground-type counter. Unfortunately, appearing at a very low level and having a very slow experience curve makes it very hard to make Exeggcute useful in-game. Consider other Grass- or Psychic-types to help you beat the remaining gym leaders and Elite Four.
If you should choose to use an Exeggutor, you'll see why it's so highly regarded in the metagame. Its typing resists Psychic and Ground type moves alike, it is one of the game's more versatile Pokemon, and it can learn some very impressive moves. It can learn Hypnosis and Sleep Powder, which is useful when combined with Dream Eater. Teaching it Psychic (via TM) is recommended, as it is a very powerful STAB attack when combined with Exeggutor's great Special stat. Mega Drain, with the added STAB, is surprisingly powerful, and is good for recovering health. Rest also can be used to recover health, as can Leech Seed. If heavy firepower is needed, try using Hyper Beam. And if all else fails, it can even learn the mighty Explosion.
Cubone and Marowak
As adorable as they are rare, Cubones are seen infrequently in Red and Blue and almost never in Yellow (although in that version only, they're also found in the Safari Zone). The decent Ground-type skill Bone Club comes built in, but better attacks like Bonemerang and Thrash (which does heavy damage, but confuses Cubone) don't come until higher levels. Cubone is better in Yellow, since he learns Headbutt at level 18!
If you use Marowak, be aware of its stats. It has good Defense, middling Attack, and poor Speed and Special. Bone Club and Bonemerang are fine, but try teaching Earthquake via TM when available. For a secondary attack, either Thrash or Headbutt should be used until you can teach Strength. Other possibilities include Focus Energy, Seismic Toss, Counter, and Fissure.
Hitmonlee has an impressive repertoire of Fighting-type kicks. The Jump Kicks do solid damage (although misses occasionally backfire to damage him), and the Rolling Kick, while not as strong, can stop enemy attacks before they begin. Speedy and powerful, he's among the best of the Fighting Pokémon, if not the best in the game.
If you use a Hitmonlee, Jump Kick and Hi Jump Kick are must-haves, being the strongest Fighting attacks in the game. Like many other physical fighters, Strength and Body Slam both allow for some variety. Other than that, there's nothing really outstanding. Consider teaching Seismic Toss and Counter.
In addition to the multiple-hit Comet Punch, Hitmonchan learns Fire, Ice and Thunder Punch skills, which do damage of the appropriate type and, 10% of the time, Burn, Freeze or Paralyze your foes. While this versatility is nice, these skills rely on Hitmonchan's dismally low Special, seriously hampering their effectiveness. Worse, Hitmonchan learns no regular Fighting moves, meaning he lacks any attacks with STAB. Hitmonlee is probably the better choice.
If you choose Hitmonchan, try to replace its elemental punches with more useful moves. Strength or Body Slam works well as a Normal-type move, but Mega Kick is also an option. Submission is the best Fighting move available, so it's a must. Seismic Toss has its uses, but considering how Hitmonchan's best stat is its attack, you won't want to rely on it too heavily. Also consider teaching Agility and Counter. And if you have an extra slot available, why not keep one of the elemental punches? If you're lacking a Fire, Ice, or Electric Pokemon, it could help ease the pain.
Lickitung is a hearty fellow, but has a number of problems. It lacks the sheer power of other Pokemon, and is slow to boot. That said, it can develop its own strategy to make it on par with other Normal type Pokemon, although it will never be able to go on par with Tauros.
Lickitung's basic arsenal of attacks includes Stomp and Slam to deal STAB damage, Supersonic and Disable to disrupt enemy plans, and Defense Curl and Screech to compensate for its low stats. You'll want to teach Lickitung a better Normal move like Strength ASAP. Screech works well, but consider teaching Swords Dance using the appropriate TM. Hyper Beam is handy as always, particularly with the STAB and a Swords Dance or Screech backing it up.
Lickitung can also learn Fire Blast, Surf, and Ice attacks via TM. However, its low stats make it hard to suggest teaching these. In order to deal damage in the late or competitive game, Lickitung needs to take advantage of its typing.
Koffing and Weezing
Team Rocket's bizarre affinity for these gaseous blobs is probably one of the reasons they lose so much. To be fair, evolved Weezing is probably the best of the pure Poison Pokémon, what with their great Defense and ability to learn Sludge, but that still doesn't make them particularly useful.
Koffing should start with Sludge, the game's best Poison attack. At higher levels, fear Weezing's Selfdestruct and Explosion skills... Too bad their most powerful attacks knock themselves out too! TMs can be used to teach an assortment of moves, like Thunder, Fire Blast, and Hyper Beam.
Rhyhorn and Rhydon
Rhyhorn's low level, low Speed and Special, late evolution, lack of non-TM STAB moves, and many weaknesses mean Rhyhorn can't really shine in game. However, its evolved form is a true staple of competitive Pokemon. Rhydon has some of the most impressive stats in the game, with an outrageous Attack and Defense, and great HP to boot. Rock + Ground is an extremely destructive attacking combo, and is essential defensively too to stop powerful Electric-types like Zapdos and Jolteon, as well as check Normal-types like Tauros and Snorlax. It might not be impressive against the Elite Four, but raise one up to trounce your friends in link cable battles.
If you choose to use a Rhyhorn in-game, you'll find that the line naturally relies heavily on Normal attacks. You star with Horn Attack, eventually pick up Stomp and Fury Attack, and very late in the game, get Take Down. Along the way, Rhyhorn/Rhydon will learn Horn Drill, a risky but viable move. With this monotonous moveset, you'll want to use TMs and HMs as much as possible. Strength is a must, as is a Ground-type move like Dig or Earthquake. Rock Slide is also quite good if you can get it. Surf can also be taught, but don't bother; Rhydon's Special is so low, it'll have trouble taking on other Rock/Ground types with it.
Here are some of Chansey's highlights. She may look absolutely ridiculous, but her Hit Points are literally off the scale, and best of all, she's the only Pokémon in the game who can learn Softboiled. That obscure skill comes from TM 41, (get it by surfing across that pool in Celadon City), and can heal your other fighters outside of battle! That's an incredible ability... It's too bad Chansey's so weak in battle, with the lowest Attack and Defense in the game (but an OK Special). Low Speed and offensive abilities make her a poor choice for the in-game adventure. Despite these failings in-game, Chansey is a staple of the competitive environment. Her incredible Special bulk makes her irreplaceable when dealing with Special Attackers like Starmie, Alakazam, and Lapras. If it is attacking on the Special side, you can at least switch in Chansey and Paralyze it with Thunder Wave, making fearsome enemies much easier to deal with.
If you decide to use Chansey in-game, it will be most useful as a counter to Special-attackers, including Psychic Pokemon. Teach it a TM like Thunderbolt or Ice Beam to give it a decent attacking option, and base the rest of its strategy around its unique style of play. Perhaps you will want to teach it Toxic, and let it use Softboiled to ensure it survives the rest of the match while waiting the opponent out. Maybe Counter could work as a way of dealing with physical fighters. Seismic Toss can compensate for its low Attack power.
Grass Pokémon are good against Water, Earth and Rock, and fairly resistant to a couple of other types. So they're pretty good in some situations, but Tangela is nothing special. They appear really late, and don't have stats to rival even Victrebel or Vileplume, and are far inferior to stronger Grass-types like Exeggcutor and Venusaur. In Yellow though, it has an added bonus, since that's the only version in which Tangela can learn Vine Whip.
If you use a Tangela, be sure to teach it Mega Drain via TM. This will be a great way to take advantage of its typing. Also try to have at least one status inducing move, like Sleep Powder or Stun Spore. Bind, a move similar to Wrap, can be used to irritate and slowly whittle down enemies. Also consider using Growth to raise Special and Body Slam to replace the naturally learned Slam if possible.
If you like goofy-looking Pokémon, you will definitely like Kangaskhan. Her attacks aren't great, but at least she can use a lot of Hitmonchan's Normal attacks (including the built-in Comet Punch) without having to deal with her general feebleness in other areas. But for a normal Pokémon, Tauros certainly has better stats.
The best reason to pick a Kangaskhan over a Tauros is its ability to Surf, so even if you already have a Surfer, consider teaching Kangaskhan. The problem is, Kangaskhan's special is so low, it won't be that effective against even Rock/Ground Pokemon like Onix and Golem, although they will still be taken out by a couple of hits. Besides that, Kangaskhan can learn Body Slam, Strength, Hyper Beam, Earthquake, and Counter.
Horsea and Seadra
Horsea's evolved form Seadra is a solid fighter, and learns a good variety of Water-type attacks. But you probably won't want more than one or two Water-types on your bench, and there's a variety of better options. Wartortle and Cloyster top the list.
Horsea and Seadra's main problem is not their stats, which are acceptable besides the HP, but their movepool. It simply lacks anything spectacular. Therefore, it'll have to rely on Surf and your favorite Ice TM to do damage, rather than anything cool like Starmie's Thunderbolt. At least there's Smokscreen, which lowers Accuracy, and Agility is potentially useful.
Goldeen and Seaking
So you might wish to ignore the less-interesting Water Pokemon ones like Goldeen. Evolved form Seaking is fairly tough, but with nothing but a handful of ordinary Normal attacks, she's not that intriguing.
If you decide to use a Seaking, it should know at least one physical Normal move; after all, that's what it's good at. Unfortunately, it only really learns Horn Attack by itself, so you'll want to use a TM to teach Take Down or Double Edge if possible. It also learns Waterfall by itself, but Surf renders that move obsolete. There's also Horn Drill, which has a 1/3 chance of knocking out an opponent in one hit. But in general, Seaking is lacking in options.
Staryu and Starmie
Staryus also evolve with a Water Stone and also gain a second type, Psychic. The evolved form, Starmie, has a really high Special, so it could make good use of its Psychic abilities... If it had any (besides Light Screen, that is). A great Pokémon, but only if you're willing to use a lot of TMs to teach it the necessary skills.
By itself, the only notable attacks Staryu learns are Swift, Recover, and eventually Hydro Pump. Unfortunately, Starmie's stats are Special oriented, making Swift less valuable, and it learns Surf via HM, making Hydro Pump less useful. That said, it can learn some very useful TMs. Most notable is Psychic, which takes advantage of its secondary typing, and Thunderbolt, an unusual move coming from a Water Pokemon. You'll also want to keep Recover, since the move is simply that useful unless you plan on using a lot of items. Other notable TMs include Ice Beam, Blizzard, Thunder Wave, Tri Attack, Reflect, Light Screen, and Hyper Beam.
Since it's an easy trade, you should definitely pick up a Mr. Mime. It doesn't have many good moves and it can't evolve, but its trademark attack, Substitute, in which it creates a clone that fights for it, is pretty cool. As far as actual combat goes, Mr. Mime is pretty useless, mostly resembling a weaker Alakazam with some curious moves. If you're looking for an attacking Psychic-type, you might as well keep the Abra you would trade for Mr. Mime.
Instead of the Pinsir in Blue, Red players get Scyther (Yellow players can get both). Scyther is part Bug and part Flying, an unfortunate mixture in that it leaves him vulnerable to six different attack types. He's quick, sturdy and strong on the attack, but like Pinsir comes with no Bug-type attacks. His weaknesses make him a little risky to use under normal circumstances, but he sure looks cool.
If you use a Scyther, you'll be pleased to know that it has impressive Attack and Speed stats. Used well, it can wipe out an entire team, provided it doesn't take him out in one or two hits thanks to its many weaknesses. Scyther learns Slash, Swords Dance, and Agility naturally. One Swords Dance will make it the strongest thing on the battlefield, while a single Agility will make it the fastest. Its only problem is that Slash doesn't work well with Swords Dance. Fortunately, it can learn other moves via TM. Cut is a surprisingly decent choice, particularly in-game, but more powerful moves like Take Down, Double Edge, Swift, and even Hyper Beam are also available.
Jynx, possibly the strangest of Pokémon, has a unique combination of types: Ice and Psychic. It has good Speed and Special, but its Attack and Defense are mediocre, and only get worse later in the game. It's the only Ice-type until fairly late, and it has more Ice-type attacks then some of its brethren, but there are better options later on and it gets no Psychic-type moves at all (unless you use a TM.) A good choice, but you could do better. Try and make sure that the Poliwhirl you trade is under level 39, or else your Jynx will lack the sleep-inducing Lovely Kiss attack.
If you do decide to invest in a Jynx, then you'll find it capable of filling two valuable niches: Ice and Psychic. Lovely Kiss is a must, thanks to the power of Sleep, but also invest in teaching it Psychic as well as an Ice move like Blizzard. This will give it two STAB moves that take advantage of its decent Special stat.
Electabuzz is pretty good. Not as good as Zapdos or Jolteon, but if you want to go crazy with the Electric-types, you'll find Electabuzz's Speed and powerful techniques a welcome addition to your team. He lacks much in the way of a diverse movepool, but at least he can learn Psychic, a useful move for almost any Pokemon with the sufficient Special stat. But be warned, his defenses are low. For your fourth move, consider teaching Electabuzz Counter, taking advantage of its own low Defense.
Magmar is both hard to catch and exclusive to Blue, but that doesn't necessarily mean he's any good. Arcanine is probably the best of the Fire Pokémon (although Blue players would need to trade for one), but Charizard, Ninetales (if you didn't evolve him until after learning Flamethrower as Vulpix) and possibly even Flareon are all better picks than Magmar in Blue. That said, there are redeeming qualities to him, so if for some reason you want one in your team, go ahead.
Magmar has a number of options open for Fire attacks, starting with Ember, learning Fire Punch and Flamethrower naturally, and also possibly learning Fire Blast via TM. Flamethrower and Fire Blast are the best picks, although Ember and Fire Punch are good while you're training. Besides those moves, Magmar's best naturally learned move is Confuse Ray, giving it a bit more of a niche than other Fire Pokemon. Furthermore, no Fire Pokemon with Confuse Ray has a higher Attack than Magmar, meaning it's a good idea to teach him some good physical move, like Strength, Body Slam, or Hyper Beam. Also consider teaching Magmar Submission, Seismic Toss, Psychic, and Smokescreen.
Pinsir, available only in Blue and Yellow, is the strongest of the straight Bug-type Pokémon. This is isn't really notable since Pinser gets no Bug-type attacks, but still is vulnerable to all four of Bug-type's weaknesses. Pinser has decent stats, but it is basically a late-to-appear, low-level Normal-type with no STAB and more weaknesses. Not worth the effort to hunt down outside the Pokedex.
The important thing to know about Pinsir is that it's a physical powerhouse, but little else. Its Attack is higher than any other non-evolving Pokemon, and its Defense is pretty good too, but HP and Special are just poor. The solution: focus on what its good at. Pinsir starts with Vicegrip, not a bad move, and should either quickly or immediately know Bind (in Yellow version only) and Seismic Toss. Seismic Toss provides coverage to whatever Normal moves don't, and does a decent amount of damage anyway. Later on, Pinsir eventually learns Slash, which can easily be its main attack. Beyond this, Pinsir can be taught several TMs. Level 54 brings Swords Dance to the table, and although this move doesn't work well with Slash in first Generation Pokemon games due to the exact mechanics, it does work well with Strength. Submission, if you still have the TM for it, gives Pinsir the ability to crush Rock and Normal types, while its typing leaves it less vulnerable to Psychic attacks than most Pokemon with Fighting moves. Guillotine is naturally learned, and has a 1/3 chance of KOing an opponent, so it should at least be considered.
Yet another Safari Zone Pokemon built for competitive battles, rather than in-game battles. Tauros come at a low level, and are extremely difficult to capture, making adding one to your team quite the challenge. Furthermore, they don't learn anything but Normal-type attacks on their own. However, Tauros has a fantastic Attack stat, and is one of the fastest Pokemon around (which means it also has one of the highest critical hit rates around).
Tauros naturally learns Stomp and Take Down, which should be replaced by Strength or Body Slam and/or Hyper Beam at earliest convenience. Awesome Speed and power, combined with its high chance to get critical hits and the sheer power of Body Slam and Hyper Beam make Tauros king of competitive battles. It also gets Earthquake and Blizzard, making it a fearsome foe even to Ghost- and Rock-type enemies. Other options include Fire Blast, Thunderbolt, and Rest.
Magikarp and Gyarados
The thing about Magikarp is that they're completely horrible. They come with only one move, Splash, and it does literally nothing. Magikarp can't learn any TMs or HMs and they don't even learn a real attack, Tackle, until level 15!
However, if you can get one to level 20, it will evolve into Gyarados, a Water/Flying-type with great stats and a small but useful move pool that includes the powerful Hydro Pump (and several more great moves by TM.)
Gyarados has fairly good stats all around, but is particularly good at physical Attacks. For this reason alone, it should be taught the mighty Hyper Beam. Also be sure to teach it moves like Surf, to take advantage of its water type, Thunderbolt, to counter other Water Pokemon, Body Slam, to deal serious physical damage and paralyze foes, and maybe Blizzard, if only because that move is so useful. Some choose to teach it Earthquake to deal with Electric types quickly.
Lapras comes at a very low level of 15, making it very impractical to incorporate into your main team. In-game, you will be better served by picking up a Dewgong from Cinnabar or Cloyster from the Seafoam Islands. However, competitively, Lapras's excellent offensive power, ability to learn Thunderbolt, and absolutely incredible overall bulk put it in a class all its own above its fellow Ice/Water brethren. Even if you do not put it in your line up, carefully stash this gem in your box.
When you do use Lapras, you will find that it has impressive stats, particularly HP. Its only weakness is a moderate Speed. Not bad for a Pokemon lacking an evolution! Surf is an obvious choice for Lapras, taking advantage of its typing. Either Ice Beam or Blizzard should also be taught, taking advantage of its other type and providing a powerful alternative to Surf. Body Slam works well for a physical move, and Confuse Ray is a useful status inducer. Also consider teaching Rest, Thunderbolt, Hydro Pump, and Hyper Beam.
Ditto is fun as a novelty, but is nearly worthless in combat. He only knows one skill, Transform, which he can use to make himself a mirror image of his opponents. The only problem is that he keeps his own low stats, so the original will trounce him nine times out of ten unless you're extremely skilled. Its only notable upside is the ability to scout out an opponent's moves, but its stats are so low, it might not even last long enough to do any reconnaissance.
Eevee, Vaporeon, Jolteon, and Flareon
As Yellow players have learned from their many confrontations with their rival, Eevee, in its basic configuration, is not especially powerful. It's just another pure-Normal type in a game with plenty of them. Their most notable trait is the ability to evolve into one of three much more powerful forms.
Water-type Pokémon are extremely valuable in the late game, and Vaporeon has one of the best Special stats of any Water-type. If you saved the Bubblebeam TM, Vaporeon will be immediately useful, and even more powerful soon after when you get the Surf HM. Celadon City even lets you access the Ice Beam TM, which will make Vaporeon a lethal threat, even to Erika's Grass-types that normally have an advantage against Water-types. With its impressive mix of defense and offense, Vaporeon is sure to make a huge splash!
Like most Water Pokemon, Vaporeon should be taught Surf at earliest convenience. Useful naturally learned moves include Aurora Beam, which can be used instead of Ice Beam or Blizzard if necessary, Acid Armor, which doubles Defense, and Haze, which negates all stat-adjusting moves. Other useful moves that can be taught via TM include Ice Beam, Body Slam, Rest, and Mimic.
The Thunderstone creates Jolteon, one of the game's fastest Pokemon. Jolteon's impressive Special and awesome critical hit rate (thanks to its Speed) make its Electric-attacks truly terrifying. You'll rarely find anything faster. Make sure you saved the Thunderbolt TM if you plan on using it. Thunderbolt alone can take on most foes, but even with its low Attack, there are some other options. Most notable are Pin Missile, which makes Jolteon a surprisingly solid counter for Psychic Pokemon, and Double Kick, which can counter the various Rock/Ground enemies you may find in your travels. Also consider teaching Thunder Wave, Take Down, Body Slam, and Sand Attack to fill that final slot.
Flareon is the red-headed step child of the Eevee evolutions, ever disowned by Gamefreak. Flareon comes with an incredible Attack stat, but all it can use it with are Normal-type attacks, and without STAB it only hits about as hard as Raticate or Pidgeot. Meanwhile, on the special side, it only gets the very weak Ember, and no better Fire-type moves until much later in the game. Defensively, poor overall bulk and low Speed gives it real problems both against strong opponents and over long routes. By the time it learns Fire Blast or Flamethrower, there are almost no opponents Fire is good against. Unless you need the Pokedex entry or just feel sorry for it, you're best off passing up on Flareon.
Porygon, who can only be acquired through coin redemption, isn't the toughest Pokémon, but his trademark skills Conversion, which makes Porygon the same type as his opponent, and Sharpen, which raises Attack power, have some interesting possibilities. He can also learn a few decent attacks and use a variety of TMs.
Porygon starts with Tackle and its two signature attacks. As it grows, it will learn Psybeam, Recover, Agility, and Tri Attack. Tri Attack and Psybeam work well, since they take advantage of Porygon's STAB and take out everything its weak against respectively. As you Porygon grows into a member of a set team, however, it will need to find a special niche. One possibility is using Sharpen to make Porygon into a Physical brute, capable of using powerful Tri Attacks and TM moves like Hyper Beam. Alternatively, you might want to teach it powerful Special moves such as Ice Beam, Thunderbolt, and Psychic, making it a sort of jack-of-all-trades. Either way, you'll want to keep the move Recover unless you plan on spending a lot of money on Super and Hyper Potions.
Omanyte and Omastar
If you took the Helix Fossil in Mt. Moon, you'll get an Omanyte, which will evolve into Omastar at level 40. Like Kabutops, Omastar is a mix of Water and Rock-types, without many good skills. Omastar's Special and Defense stats are a bit higher (Kabutops excels in Attack), but both are equally unexciting in most respects.
Surf is an essential part of Omastar's moveset, but beyond that you have few great options to make. Blizzard is always handy, as is Seismic Toss, but something like Rest could also work thanks to its high Defense. Also consider Horn Drill if you're feeling lucky.
Kabuto and Kabutops
The scientist in the Pokémon Lab will turn the Dome Fossil into a level 30 Kabuto, which evolves into a hardcore Kabutops at level 40. If only Kabutops was half as cool as he looked! Stats-wise, this guy's tough. But except for Slash (level 39) and Hydro Pump (level 53), he doesn't have much in the way of skills. And Rock/Water is a kind of lame mix of types, especially since he doesn't actually learn any Rock techniques.
If you do pick up a Kabutops, be sure it learns Surf, to take advantage of its typing as much as possible. Swords Dance combined with a move like Body Slam or Take Down can be devastating. Hyper Beam, Slash, and Blizzard are also available.
Aerodactyl is a very fast Rock/Flying Pokémon. Aerodactyl's only useful stat is his incredibly high Speed, the third highest in the game. He has great Attack, but he gets few STAB moves to use it with. His other stats are relatively low and he has many weaknesses.
At level 54 Aerodactyl learns Hyper Beam, but until then, its best to teach him a move like Fly (STAB; using HM02) or Fire Blast (TM38). Aerodactyl can also learn Sky Attack (TM43), but since it is a charge move, its better to wait for Hyperbeam and not waste a TM. Most of the attacks that Aerodactyl can learn either require Aerodactyl to charge up for a turn, or have recoil damage associated with it.
He's decent against Blaine's Fire beasts, but being weak to Ice, Water and Electric attacks, you may not want to bring him to the Seafoam Islands or the Power Plant. That said, this is one great late-game Flying Pokemon, assuming you don't want to use one of the Legendary Birds.
There's only two Snorlaxes in the game. He'll learn some okay attacks at level 35 and beyond, but early on he's mainly defensive. He has a ton of Hit Points and comes with Rest.
As Snorlax grows, he becomes a surprisingly capable fighter, and arguably the greatest pure-Normal type for in-game use. It starts off with Headbutt, which does significant damage. Amnesia, when combined with its high HP, makes it largely invulnerable to Special Attacks, especially when Rest is available to recover all health. Things only get better as it grows and TMs become available. Naturally, it learns Body Slam to replace Headbutt, and eventually Double Edge and Hyper Beam for riskier and more powerful options. From TMs and HMs, it can learn physical moves like Earthquake and Selfdestruct, which take advantage of its high Attack, or Special moves like Surf, Thunderbolt, and Ice attacks, which take advantage of Amnesia.
Ultimately, Snorlax is really only weak against powerful fighting Pokemon; it has the tools to take on everything else. The only problem it'll have is its horrendous speed, which no amount of training can overcome.
Like Zapdos, level 50 Ice/Flyer Articuno has strong stats, especially Special, and learns his best technique (Blizzard) at level 51, almost immediately. Its Ice Beam and Blizzard are the game's strongest, and other attacks like Fly and Double Edge are also sufficiently powerful for anything in the game. That said, it is relatively vulnerable to Fire, Rock, and Electric attacks.
Zapdos is incredible. He starts at level 50, learns the most powerful Electric technique (Thunder) at level 51, and he has a beneficial mix of types: Electric lays waste to everything but Ground and Grass, two things the splash of Flying-type gives Zapdos protection against.
Zapdos's natural moveset, which includes both Drill Peck and Thunder by level 51, is strong enough to deal with any foe save for Rock/Ground Pokemon. Beyond that, you'll need to fill up the remaining two spots with something, so here are some options. Fly is weaker than Drill Peck, but is convenient for traveling if for some reason you lack a Flying Pokemon. Thunder Wave can be taught via TM. Other useful abilities include Rest, Agility, and Thunderbolt to replace Thunder.
The strongest Fire Pokemon in the game. Moltres uses a combination of FIre Spin to trap enemies and Fire Blast to destroy them. Its Sky Attack provides it with a way of dealing heavy physical damage, and Agility makes up for its unremarkable Speed. However, Moltres lacks the diversity of some other Pokemon, only learning five moves naturally. Furthermore, it can be quickly fell by a solid Rock attack, thanks to its 4X weakness to the element.
Dratini, Dragonair, and Dragonite
The Dratini family are the only Dragon-type Pokémon in the game. As types go, Dragon gives good defensive bonuses because it has resistances to Fire, Water, Electric, and Grass, and is weak only to Ice. On the downside, there aren't really any Dragon-type attacks for them to take advantage of (except for Dragon Rage, which does 40 damage, no matter what type the user is). Coming so late and at such a low level, Dratini are not much use in-game, but the fully evolved Dragonite can be a real nuisance in competitive matches by using its bulk to set up Agility and abuse Wrap. Plus, Dragonite has the highest stats of any non-Legendary Pokemon in the game, making it a rewarding investment.
Once fully evolved, Dragonite has a variety of options. Wrap, of course, is a great irritant to enemies, particularly when paired with Agility. It may lack any STAB moves, but it makes up for it with powerful attacks like Hyper Beam, Fire Blast, Blizzard, Thunder, Surf, and Strength. Incidentally, these moves also cover its chief weakness: a 4X vulnerability to Ice attacks
Mewtwo is the absolute best Pokémon in Red, Blue and Yellow, with phenomenal stats in every category, especially with an extremely high special and excellent speed. Nothing can stop this Pokémon, nothing.
- Ice Beam
Mewtwo, already an extreme terror that it is already, can be a user of Amnesia, which raises a user's Special by two stages (which is doubling the stat). With just one Amnesia boost, Mewtwo's massive Special will increase to ridiculously extreme levels, just enough so that it can have the power to OHKO almost anything. Have Psychic for Mewtwo's main attack for STAB power, which will easily destroy almost anything. Have Recover so it can heal up damage. Ice Beam could be used to hit on various other Pokémon that have a weakness to Ice-type attacks. Now Thunderbolt could be an option over Psychic or Ice Beam, which can hit hard on the many Water-type Pokémon about in this game. In addition, very few Pokémon are able to resist both the latter two such as Starmie, Slowbro and Jynx so they can counter Mewtwo. Despite being not so favorable in coverage, Psychic is the better option in terms of power, while Ice Beam has better coverage. If your willing to forget Recover for Thunderbolt, then Mewtwo can use all three move along with Amnesia for massive power and good coverage despite having no healing move when it takes hits.
- Other Options
Mewtwo has some other options thanks to its fantastic movepool of utilizing many strategies. Blizzard can be an alternative for Ice Beam in the Amnesia moveset, which give more power but a bit less accuracy and PP so Ice Beam is still the more reliable choice. Fire Blast is a powerful Fire-type attack and it should hit any Grass-type Pokémon pretty hard.
It has a good Attack as well so Normal-type attacks such as Body Slam, Double-Edge, and Hyper Beam can come in handy against ones with poor defenses, while Submission, a Fighting-type attack which causes recoil damage, can be used to weaken Normal-type Pokémon such as Chansey and Snorlax.
Defensively, Mewtwo can use Barrier or Reflect to raise its defense (its only stat where its poor at), and Thunder Wave, as always, is such a great move in RBY period for paralysis inflicting. Substitute is also useful although it doesn't block status inflicting.
There are literally no true counters to RBY Mewtwo, its not easy stopping the destructive thing although since this is Generation I, you can try to get lucky. In order for Mewtwo to be ever taken down, its best to inflict it with a status such as paralysis or sleep (freezing permanently disables a Pokémon until a Fire-type move or haze were used on it). Chansey is a decent option, with Light Screen, she can try to take in some of Mewtwo's attack and try to use Thunder Wave or Ice Beam to freeze it; Mewtwo is still capable of hitting hard on Chansey however, as it has Amnesia and a very high critical hit rate. If Mewtwo lacks a Ice-type attack, Exeggutor can use Sleep Powder on it.
You can also use other Psychic-type Pokémon such as other Mewtwo, Starmie, and Slowbro, the latter two are Water and Psychic which could resist Psychic and Ice Beam/Blizzard set and they can hopefully inflict it with paralysis. If it has Thunderbolt, well, not so much with the said latter two. Mewtwo's weak stat is its Defense, so if you don't think status inflicting is enough, try to hit Mewtwo with a physical STAB attack.