I would include:
A bomb from SF64, which is like a Bob-omb, except detonates after three seconds after thrown or when B is pushed
A potion from Pokemon, which recovers 20HP
FLUDD; used to shoot water in any direction, can be used as another jump. Direction controlled by control stick.
Poltergust 3000; like Kirby, except you can suck the opponent in, drain health, then spit them out again
A balloon, used to float in mid-air, controlled with control stick.
The classic Bumper >:D
The selection glove from SSB, which picks up the closest player and throws them
More to come.