Crates and Barrels: What better to start with than basics. These item containers have been revamped to support the themes of certain levels.
Assist Trophy: This is the Pokeball of the Nintendo Universe. Any kind of cameo you could think of comes from within...
Known Assist trophies:
Pokeball: An alltime favorite. Which still randomly gives you a poke to cause massive destruction with.
Gooey Bomb: The Gooey Bomb acts as a sticky Remote Mine. While stuck to a character, it can be passed back after making contact with another player.
Cracker Launcher: This projectile launcher isn't as racist as it sounds. It might be more recognizable as a 'Roman Candle'. We saw it briefly in the short clip from Min-E3.
Banana Peel: Because Cliche's work.
Bumper: A return from the 64, relatable to Melee's Flipper item. A new twist leaves this possible to plant mid-air.
Pitfall: The item from Animal Crossing. Surprisingly, it caries its ability from Animal Crossing over very well. Simply making characters fall thru holes or thru platforms.
Smoke Ball: An original item, soley based on obscurity. This item deals no damage, but rather actually just blinds the player from the screen.
Franklin Badge: Debuting from the Mother Series (Earthbound), this relates to Fox's Reflector, like the Screw Attack Ball relates to Samus' Screw Attack. Basically, it reflects projectiles.
Spicy Curry: When a Fire Flower just can't suit your flaming needs.