The green shell. Basically a missile. It can be shot both forwards and backwards, going in a straight direction. Being hit by it will cause a crash. It can be held behind you to shield you from other shells.
Three green shells. The main difference between this item and a regular green shell is that these shells can't be thrown backwards. They can create a good shield because they rotate around you blocking anything from hitting you.
The red shell is like the green shell in many ways, but instead of flying straight out, it will home in on the nearest player. It can also be held behind you as a shield.
Three red shells. The same as triple green shells, except red.
A trick item block. Place it on the track to trick people into running into it. Instead of getting an item from it, you just crash.
A banana. If ran over, it will cause your kart to spin out of control. You can avoid crashing by slowing down right after hitting one. They can be used as a shield and also thrown forwards or backwards.
A group of bananas. Same effect as bananas.
A mushroom that boosts your speed temporarily.
A trio of mushrooms that boost your speed temporarily.
An amazing golden mushroom that lets you boost your speed repeatedly for up to 30 seconds. It's an extremely useful item that can bring you up to the front of the race.
A star that makes you invincible to all items. It also boosts your speed up. Its effects end after a short time, or when you fall off a ledge.
Using this item will steal an item from another player. It also temporarily makes you invulnerable to other items.
A lightning bolt that hits everybody but the player who uses it. It shrinks anyone it hits causing them to slow down. Shrunk players may also be run over.
A special shell that zooms to the front of the race to hit whoever is in first. It is extremely hard to dodge, and if used while you're in first place, it will come back and hit you.