I got some ideas for Pokemon that come out of Pokeballs-
Weak Damage
Pichu - Thundershock - shock nearest foe - 10%
Corsola - Spike cannon - Releases spikes which hit random foe, including yourself! - 5% for each spike hit
Ratatta - Quick Attack - weaker version of fox illusion - 10%
Medium Damage
Staravia - Wing Attack - Flies around the area at random foes - 20% each hit
Vespiquen / Combee - Attack Command - Sends many Combees to swarm around the screen, attacking opponents - 15% each hit
Heavy Damage
Sceptile - Leaf Blade - Jumps around the arena slashing foes with it's arms - 50% Damage
Uxie - Psychic - Flips Opponents over and does lots of damage if touched - 25% if flipped over, 75% if touched
Mesprit - couldn't think of one xD
Azelf - Uproar - does heavy damage but weakens if released from pokeball again - 50% damage, looses 10% damage every time it's released again
Swampert - Muddy Water - makes a huge wave crash onto the battlefield - 50% damage
Random / Unpredictable Damage
Hoothoot - Hypnosis - makes foes nearby fall asleep for *insert seconds here* - no damage unless you attack sleeping foes
Kicketot - Bide - absorbs everyones attacks and fires them back at random foes - depends on what attack you are hit with
Ditto - Transform - transforms into a random pokeball pokemon - random damage
Control / Health Effecting
Manaphy - Heart Swap - Flips controls around (A becomes B, L and R become X and Y, Up becomes Down, Left becomes right, etc.) - no damage
Misdrevous - Pain Split - Splits all health evenly - no damage
Blissey - Softboiled - Restores a random person's Hp all the way to 0% - uh.. negitive damage?
Score Effecting (unlocked after centain events)
Jirachi - no attack - gives the person who sent it out of the pokeball 50000 points ad a Jirachi Trophy
Shaymin - no attack - give the person who sent it out of the pokeball 50000 points and a Shaymin Trophy
Plus all the previous Pokeball Pokemon such as Clefairy, Marril and Chansey