Assist Trophy
Assist Trophies are a breed of new items that are very similar to Poké Balls. They send out various characters from different games to attack other players or to help you in some way. Some characters will hinder you, however. A complete list of known Assist Trophies are listed here.
Banana Peel
Another new item for Brawl, it simply won't let you run freely on the stage.
Bunny Hood
Returning from Super Smash Bros. Melee, the Bunny Hood from The Legend of Zelda: Ocarina of Time will increase the speed and will let the character who wears it to jump really high.
Bumper
Nine years have passed since Super Smash Bros. was released, and with SSBM some items were forgotten. Well, now is the time for all the ones who didn't have SSB to use this veteran item. The Bumper is the closest thing to a pinball game and you can place it on the ground or in the air. If you hit it you will bounce to the other side.
CDs
CDs appear in every game mode, and add new music to be selected when taken.
"Clear form"
The Special Brawl menu lists a form called "clear", meaning that the ability to become invisible will still be in the game, but it's unlikely that the Cloaking Device from Melee will return, giving its origins from Perfect Dark; a game created and owned by Rare, which now works for Microsoft.
Cracker Launcher
Another new addition, the Cracker Launcher shoots off fire crackers that explode. The Launcher can be aimed up and down for the best firing angle. This gun-item also has the ability for the user to walk around and jump while firing.
Crates and Barrels
The crates and barrels have appeared since the first Super Smash Bros. Barrels from all Smash Bros. have had various amounts of different items inside each. You can get the items by throwing the box or crate, beating it up, or pushing it off a higher area to a lower area. Some added features in Super Smash Bros. Brawl is that the basic box style changes for each level, so you can have space boxes in a Star Fox level, or have presents in a Yoshi's Island level. Another added feature in Brawl is that boxes will slide downhill.
Franklin Badge
The Franklin Badge, from Earthbound, reflects projectiles much like Fox's Reflector move, but automatically. The Franklin Badge wears off after a certain amount of time.
Golden Hammer
Like a normal Hammer, but more powerful and allows the holder to hover in midair.
May be look-alike Golden Squeaky Hammer that does not cause damage.
Gooey Bomb
The Gooey Bomb is an item sort of like the Motion Sensor Bomb (likely a replacement, as the Motion Sensor Bomb itself comes from GoldenEye, which was created by Rare back when they were still developing games for Nintendo), except that it can stick to characters as well as the level. One of the bad factors of this item is that if you throw it on someone, they can run into you and make the bomb stick to you.
Hammer
Seen in the Golden Hammer update, the Hammer allows the holder to cause massive damage, just like in Super Smash Bros. Melee. It may drop it's head and become useless.
Lip's Stick
Lip's Stick, originating from Panel de Pon, returns from Super Smash Bros. Melee. It can put a giant flower on top of an opponent's head, causing the precentage of the character to raise slowly.
Metal Box
The Metal Box from Super Mario 64 returns, behaving more or less the same as in Melee; pick it up to temporarily become a metal form.
Mega Mushroom
In New Super Mario Bros., the Mega Mushroom can cause Mario or Luigi to become a giant. Since the Super Mushroom in Melee acted similar to this item, the Mega Mushroom has likely replaced it, as the Special Brawl menu names the giant size "Mega" instead of "Giant" as it was in Melee.
Mini Mushroom
In New Super Mario Bros., the Mini Mushroom can cause Mario or Luigi to shrink to an even tinier size than they first started out. Since the Poison Mushroom in Melee acted similar to this item, the Mini Mushroom has likely replaced it, as the Special Brawl menu names the tiny size "Mini" instead of "Tiny" as it was in Melee.
Pitfall
This item appeared in Animal Crossing. Bury it in the ground and it becomes a trap. Throw it at the ground or at an opponent and they get stuck in the ground or fall through dropable platforms.
Poké Ball
Like the previous games the Poké Ball will release a Pokémon which may be Pokémon from Generation I to IV. A list of Pokemon known to be appearing is here
Smash Ball
Grab a Smash Ball to release a Final Smash. Since these items are very rare, they do extreme damage to most player who come into contact to the character who recieved the Smash Ball's attack.
Bowser
Giga Bowser Trasformation: Bowser transforms into Giga Bowser (Super Smash Bros. Melee), making him bigger, stronger, a bit uglier, and nearly invincible.
Donkey Kong
Konga Beat: Whips out his bongos and plays with a fury that bursts your eardrums. You can play along by pressing button combos.
Kirby
Kirby basically cooks the enemy in a giant pot. (The name and the full effects are not yet known.)
Link
Triforce Slash: Link creates two giant Triforce symbols that trap a character while Link slashes them repeatedly.
Mario
Mario's Finale: Mario shoots out a vast number of gigantic fireballs that engulf any surrounding opponent.
Pikachu
Volt Tackle: Pikachu transforms into a huge sphere of electricity and flies around hitting anything in it's path.
Pit
Palutena's Army: Palutena appears and sends many Centurions from the sky to shoot arrows at the competitors.
Samus
Zero Laser: Samus fully charges her laser and unleashes a powerful beam with maximum power. After this her suit will fall off and you will transform.
Yoshi
Super Dragon: Yoshi grows wings, allowing him to fly, and starts spewing fire. Pressing a button will also allow him to shoot fireballs as well.
Smoke Ball
The smoke ball does not cause any damage, but instead obscures the screen with a cloud of smoke. Smoke balls may be carried and thrown.
Super Scope
The Super Scope is a gun that originated in Super Smash Bros. Melee. It has the ability to shoot multiple bullets quickly or charge up a huge bullet. In Super Smash Bros. Brawl, the player has the ability to jump and walk around while using the item.
Superspicy Curry
Eating superspicy curry will cause your character to begin to spew flames from its mouth, even while attacking. It also seems that extra combos will be available for your character to perform while under the influence of superspicy curry.