From Bulbapedia, the community-driven Pokémon encyclopedia.
My Music (Japanese: オレ曲 My Tunes) is a feature in Super Smash Bros. Brawl that allows the player to change the chance of each song used for the music in each stage. There are 288 background music tracks in the game, of which 13 are from the Pokémon franchise. Most must be unlocked by finding CDs during gameplay, which randomly appear or are dropped by Mew when released from a Poké Ball.
List of Pokémon music