Brawl Pokemon
Remember the good 'ol days of the original Super Smash Brothers? You were able
to use Poke Balls in the game, and you still can in Melee & Brawl. This is a list
of pokemon that appear from poke balls in Brawl and their potential.Deoxys

Deoxys arrives with a grand entrance, of flying out of the Poke Ball, fly up high in the sky, and then direct a Hyper Beam downwards that will inflict some critical damage.
Bonsly

Friendly pokemon, or dangerous weapon? You make your choice. When Bonsly comes out of a Poke Ball, you can literally pick him up, and throw him at your opponent, like an object. This guy packs a powerful punch and can knock your enemy right off the stage!
Groudon

Being one in the legendary group, this dude is huge, thus requiring no movement in this game. You could consider him to be one of the legendary 3 birds in Melee (Articuno, Zapdos, Moltres), because his attack is composed of constant stomping. His body is just like a volcano, so when any character becomes in contact with this fellow, they will be burnt.
Chikorita

One of the favorite pokemon of Grass lovers, this princess attacks with Razor Leaf in Brawl. Not much else to say, but leaves fly around her and damage your opponents.
Goldeen

Another one of those useless pokemon! Being just like Magikarp, all Goldeen does is flop around. Oh well, you may get a better pokemon next time.
Piplup

Yay, a penguin! Piplup has a really cool attack, which is Surf. Piplup surfs around the area, and if your opponents get caught, they could possibly knocked right off the stage.
Manaphy

Manaphy contains quite a weird move, which is supposively called Heart Swap. You literally switch bodies with your opponent, and the factors are pretty much switched. For example, if you're fighting as someone such as Donkey Kong, and are against someone such as Mewtwo, you'll temporarily become Mewtwo and use his moves. All of your stats such as your damage and lives will remain the same.
Munchlax

One of the first determined 4th generation pokemon! He could be considered as a Mini-Snorlax. (His evolution is Snorlax anyways.) Apparently Munchlax skipped breakfast, so now he's consuming all of the items on the battlefield! Better go grab that Smash Ball before he eats it too!
Meowth

An original move, Pay Day, was a strategy some people used to actually make money on their pokemon games. This move is rather amusing when in Brawl, because he attacks opponents with it. His coins are literally bullets!
Additional pokemon

There are some random additional pokemon that may appear in battle. When you get rarer ones such as Mew, it might possibly drop an item that you could pick up.
There are still some other Pokemon to be confirmed. If I find out that any others are going to be in the game, I will update the page.
Images provided by Ign.com. Thanks!