CDs

Hidden throughout the game there are 43 CDs. These can be found in glowing blocks around the regions rotating daily, or some can be found in CD racks in choice areas like the S.S. Anne and Pewter Museum. The CDs contain classic Pokémon music and allow for you to play them so you can hear the music

To play the music, you need a CD player and when placed, you can put a CD into the CD player and hear the music when you're within a short range of the CD player.

Alternatively, DJ Rotom can be found in the Rocky Ridges and allows for you to store up to 5 CDs in it. It will then play the soundtrack on loop from those 5 CDs whenever you're around it. If you have DJ Rotom follow you, you will be able to constantly hear the music.