RetroAchievements.org is a website where you can earn achievements for retro games via emulation. You could even sign up for a dev role to create your own achievement sets. Some homebrew developers even made achievement sets for their own games, too.
Game Boy and GBC are supported, but Commodore 16, Oric and ZX Spectrum aren't supported. I was wondering if you could consider making achievement sets for your GB and GBC ports of C16 games.