I've published a blog post with a ton of Game Boy Color chipmusic by Thomas Mogensen, a guy usually known for almost a thousand SID tunes on the Commodore 64. The blog post contains music from Jim Henson’s Bear in the Big Blue House, Jay und die Spielzeugdiebe (“Jay the Lion”), unused music for Micro Machines V3, and The Land Before Time. There are also some demo tunes not made for any game.