For cooperative games I would say Spirit Island.
For competitive, oddly most the games I like are on BGA already, Fox in the Forest is one I think would be great for BGA. It is simple and fun imo.
Unmatched would be another amazing one imo. It would be so fun to have on BGA. After thinking about it, is it possible to have games with "movie/TV licenses" on BGA? After a quick look I don't see any game with non original themes. It would be super cool to have some of the LOTR games