I don't think the PS3 has any online MMO-type games any longer. Their servers have been shut down since the games are so old.
There are still a number of games based on various anime series that are available on the PS3, such DragonballZ, One Piece, Mobile Suit Gundam, Naruto, and Fist Of The North Star, to name a few.
There are also a number of games that use anime-style characters but are not based on anime themselves. This would include Dynasty & Samurai Warriors, most JRPGs and other games from Japan, etc.
You might have a look at Oneechan-bara. It's a 3rd person brawler type game. One of the playable characters is a Japanese school girl, who fights zombies in a tattered school uniform. As I recall you could unlock additional costumes for all three of the playable characters.