Dota 2/Heroes

With over 90 heroes and still some yet to be ported from DotA, Dota 2 has a large roster of playable characters, each with their own unique abilities and playstyles.

Note that the Radiant/Dire alignment of each hero doesn't affect their availability for each faction in gameplay. It is only a feature of lore that can also be used to sort heroes.

Strength Heroes
Strength heroes have strength as their primary attribute, so they are usually very durable. This makes them great initiators as they will usually find themselves in the middle of a large fight. Their natural tankyness also makes them good supports that can stay alive despite a lack of items. They also make good carries as they do more damage while getting more hp, eventually having an immense damage output while having an inpenetrable defense.

Radiant

 * Earthshaker: Earthshaker is a strong support and initiator, packing powerful stuns as well as being great at counter-pushing with his Echo Slam.
 * Sven: Sven is a simple hero with a good stun and great buffs. He can deal tons of damage without the help of items due to his God's Strength.
 * Tiny: Tiny specializes in extreme burst damage, killing heroes almost instantly with his Avalanche and Toss combo.
 * Kunkka: Kunkka can deal great AoE damage with good aim while being a strong carry when farmed. He can set up his other spells with X Marks the Spot and initiate teamfights with Ghost Ship.
 * Beastmaster: Beastmaster calls upon his loyal hawk and boar to assist him in battle. He can scout, clear a pth through forests and blow his opponents away with a Primal Roar.
 * Dragon Knight: Dragon Knight possesses the resilience of a dragon, being able to wipe out armies with his Breathe Fire and pin down his rivals with a Dragon Tail. When the situation calls for it, he can summon the dragon within, attacking his enemies with refined elemental breaths.
 * Clockwerk: Clockwerk specializes in isolating key targets inside his Power Cogs, springing to his victim with an accurate Hookshot. He can use his Rocket Flare to scout out enemy territory.
 * Omniknight: Omniknight can cast a bunch of defensive spells to protect his allies from attacks, physical or magical. He can also heal allies in need of health.
 * Huskar: Huskar is a hero that lives life on the edge, getting stronger the closer he is from death. His Burning Spears and Life Break helps bring him to that power level, though a quick cast of Inner Vitality will bring his health back up if it gets too low.
 * Alchemist: Alchemist's greed knows no bounds, squandering tons of gold faster than other heroes. His knowledge of Chymistry also lets him melt off his enemy's armor, concoct volatile mixtures and buff up his ogre partner.
 * Brewmaster: Brewmaster is a master at fighting drunk, evading attacks which is made easier if the atacker is in a Drunken Haze. While he is quite durable normally, he can extend his life slightly longer by casting Primal Split, splitting into three warriors with useful teamfight abilities.
 * Treant Protector: Treant Protector boasts an array of support spells, though he can deal a lot of damage. He can strengthen his allies with Living Armor, drain enemy health with Leech Seed and entangle them with Overgrowth, all while under the invisibility provided by Nature's Guise.
 * Wisp: Wisp is a helpful partner for any hero, tagging along with Tether to provide additional speed, regeneration and Overcharge. Its Spirits are difficult to control but effective once mastered. Its Relocate has a lot of uses, from setting up sudden ganks to saving heroes from death.
 * Centaur Warrunner: Centaur Warrunner is very tanky and isn't afraid to do powerful Double Edge strikes that wounds himself at the same time. His Hoof Stomp is a reliable disable and his Return makes him even tankier. If he needs to cause some trouble, Stampede can be used to mess up the enemy team.
 * Timbersaw:

Dire

 * Axe: Axe is the true tank in RPG terms, forcing enemies to focus on him with Berserker's Call and roughing through everything with Counter Helix. His Battle Hunger will wear down his enemies and a swift strike of the Culling Blade is a sure death for wounded enemies.
 * Pudge: Pudge is a very capable ganker that requires some skill to play. He can drag helpless foes away from safety with his dreaded Meat Hook, force them to choke on his nauseating Rot and lock them down as he Dismembers them bit by bit. Once his Flesh Heap stacks pile up, Pudge becomes an unstoppable killing machine.
 * Sand King: Sand King can reliably stun his foes with Burrowstrike and catch his enemies in a raging Sand Storm, though he can also use this abilities to escape the most difficult situations. His Epicenter might take a while to activate, but a timely one in a teamfight can change the outcome of the fight.
 * Slardar: Slardar is a proficient hunter, weakening and tracking his targets with Amplify Damage. His Slithereen Crush is brutal, and his Bash makes it harder to fight back. Not even running will help, because Slardar can Sprint at a deadly speed to catch up with his prey.
 * Tidehunter: Tidehunter is a valued support and one hero that is useful for every teamfight. He can tear through enemy armor with Gush and weaken groups of foes with Anchor Smash. He can also survive being the center of his enemy's attention with Kraken's Shell. Tidehunter can quite literally turn the tide of the battle with Ravage, which stuns every enemy in a huge radius around him.
 * Skeleton King: Skeleton King is the simplest hero in the game with only one active ability, but that's no reason to underestimate him. He is very difficult to kill, and requires more effort to make him stay dead. His Vampiric Aura is a built-in lifesteal, and if he does die, he can even resurrect himself back in top shape.
 * Lifestealer: Lifestealer, like his name suggests, specializes in leeching the life out of his enemies. In fact, the more health his target has, the better for him. He can brush off all magic spells while in a Rage, while his Open Wounds will cripple his targets. He can also Infest a creep or an ally, bursting out at any time to give his foes a nasty surprise.
 * Night Stalker: Night Stalker is weak during the day, but at night, he becomes a deadly ganker. With superior night vision he can hunt down his targets straight from the darkness, disabling them with a combination of Void and Crippling Fear. If he needs to, he can even turn day into night for his powers to activate.
 * Doom:
 * Spirit Breaker:
 * Lycanthrope:
 * Chaos Knight:
 * Undying:
 * Magnus:

Radiant

 * Anti-Mage:
 * Drow Ranger:
 * Juggernaut:
 * Mirana:
 * Morphling:
 * Phantom Lancer:
 * Vengeful Spirit:
 * Riki:
 * Sniper:
 * Templar Assassin:
 * Luna:
 * Bounty Hunter:
 * Ursa:
 * Gyrocopter:
 * Lone Druid:
 * Naga Siren:

Dire

 * Bloodseeker:
 * Shadow Fiend:
 * Razor:
 * Venomancer:
 * Faceless Void:
 * Phantom Assassin:
 * Viper:
 * Clinkz:
 * Broodmother:
 * Weaver:
 * Spectre:
 * Meepo:
 * Nyx Assassin:
 * Slark:
 * Medusa:

Radiant

 * Crystal Maiden:
 * Puck:
 * Storm Spirit:
 * Windrunner:
 * Zeus:
 * Lina:
 * Shadow Shaman:
 * Tinker:
 * Nature's Prophet:
 * Enchantress:
 * Jakiro:
 * Chen:
 * Silencer:
 * Ogre Magi:
 * Rubick:
 * Disruptor:
 * Keeper of the Light:

Dire

 * Bane:
 * Lich:
 * Lion:
 * Witch Doctor:
 * Enigma:
 * Necrolyte:
 * Warlock:
 * Queen of Pain:
 * Death Prophet:
 * Pugna:
 * Dazzle:
 * Leshrac:
 * Dark Seer:
 * Batrider:
 * Ancient Apparition:
 * Invoker:
 * Outworld Destroyer:
 * Shadow Demon:
 * Visage: