Well it was a pretty interesting research topic you debated above. Yep finding tags for games despicting MM interactions its hard cuz bara and yaoi are kinda hard tags who dont work for everything and gay you get both sides(MM & FF) I think they could put relationship tags with subelement romance or sexual and go with (MM/MF/FF) with possibility to include A for agender and H for Hermaphodite for more coverage, and others if you want to include more genders i cant find a easy abreviation.