Welcome to the site! Firstly, the tiering sub-forum is for official tier lists and rankings - questions like this should be asked in the competitive battling sub-forum so I moved it there.
Play! Pokemon events follow a different tier list to the one we follow on the site. Most official tournaments are in a VGC (Doubles 4v4 format) with most game exclusive and event legendaries banned. On our site, we follow a different set of tiers centered around the Singles metagame.
- Mewtwo
- Mew
- Lugia
- Ho-oh
- Celebi
- Kyogre
- Groudon
- Rayquaza
- Jirachi
- Deoxys
- Dialga
- Palkia
- Giratina
- Phione
- Manaphy
- Darkrai
- Shaymin
- Arceus
- Victini
- Reshiram
- Zekrom
- Kyurem
- Keldeo
- Meloetta
- Genesect
- Xerneas
- Yveltal
- Zygarde
- Diancie
- (Soul Dew)
This is the VGC banlist