This one is kind of niche. If you own an Analogue Pocket (to play GB, GBA, GBC cartridges among others with dedicated adapters sold separately) it comes with a build-in music software called Nanoloop2. Usually to use Nanoloop2 you would buy it as stand-alone GBA cartdridge on the nanoloop2 website (https://www.nanoloop.com/two/index.html) but if you own the AP console, it comes for free, included in the premium cost of the device itself, saving 69 bucks on the standalone software. Here is a nice tutorial that explains how it works… enjoy!