Many artists and labels are constantly exploring different methods through which to release their music beyond streaming and CDs. Some have sold USB drives featuring their tunes over the last decade or so. However, there haven't been too many instances I can think of where a selection of tracks will only be available on a Sega Genesis cartridge.
Analogue, which released its own take on the classic console earlier this year, teamed up with electronic music label Hyperdub for a fun project to mark the label's 15th anniversary. They're releasing a limited-edition Mega SG console that's bundled with a cartridge that features 11 exclusive tracks from Hyperdub artists. It also comes with an 8BitDo M30 2.4g controller and a Hyperdub keychain. Only 1,000 of the consoles will be available and you can pick one up for $250.