Pokemon in the Pokeballs
The Pokemon in the Pokeballs have the following powers:

Beedrill
Flies off to get the rest of its hive to attack the opponent.

Blastoise
Blasts opponent with water spray.

Chansey
Pops out and give you an item.

Charizard
Starts to breath fire in each direction.

Charmander
Just blows fire in one direction (only in Silphco stage).

Clefable
Arrives and mimics one of the other available Pokemon's attacks.

Goldeen
Flops around trying to hurt opponent.

Hitmonlee
Comes out and flies at the opponent doing a kick attack.

Koffing
Arrives and starts blasting foul smoke in the air.

Meowth
Pops out and showers out coins that hurt opponent.

Mew
The special secret 151st Pokemon makes his appearance and flies away.

Onix
Shows up, flies up top, and then boulders drop from the ceiling.

Porygon
Rams you or the opponent (only in Silphco stage).

Snorlax
Pops out, flies up, and then comes down huge, hurting your opponent.

Starmie
Finds opponent and blasts them with rays.

Venusaur
Razor Leaf attack; leaves from this Pokemon fly at opponents (only in Silphco stage).