There is no game called "Bleach vs. One Piece". It's likely you are thinking of a crossover game where characters from both anime series could fight, but no such game exists.
There are games featuring characters from both Bleach and One Piece, but they are separate. Aizen is a character in the Bleach series, and he is not a playable character in any One Piece game.
If you are looking for games with similar crossover gameplay, you might enjoy games like "Jump Force" or "Super Smash Bros.", which feature characters from various manga and anime series.