VGM (Video Game Music) is a sample-accurate sound logging format for many machines and sound chips. It logs the commands sent to the sound chips so the resulting files are much smaller than mp3s.

Play all your favorites tracks from

https://vgmrips.net/
http://project2612.org/
http://www.smspower.org/

* Supports .vgm and .vgz files

https://github.com/VolcanoMobile/vgm-player