Some Pokémon are too uber for competetive play and are banned; however, in casual play, the use of tier 3 and 4 pokémon are allowed.
Tier GOD: 720 Total Base Stats:
Arceus
Tier 1: 680 Total Base Stats:
Mewtwo
Lugia
Ho-oh
Rayquaza
Dialga
Palkia
Giratina
Tier 2: 670 Total Base Stats:
Slaking
Kyogre
Groudon
Regigigas
Tier 3: 600 Total Base Stats:
Jirachi
Celebi
Mew
Deoxys
Dragonite
Tyranitar
Salamence
Metagross
Latios
Latias
Garchomp
Heatran
Cresselia
Manaphy
Darkrai
Shaymin
Tier 4: 580 Total Base Stats:
Articuno
Zapdos
Moltres
Raikou
Entei
Suicune
Regiice
Regirock
Registeel
Uxie
Mesprit
Azelf
List compiled by t3h n00berson~