Some of the smaller tetras (neons, cardinals, glowlights, embers), smaller rasboras (harlequins, espes), corydoras catfish, bettas, dwarf gouramis (or something like sparkling gouramis), shrimp, African DWARF frogs (not the larger frogs people commonly mistake them for), guppies (all males/females, don't mix), endlers, etc.
I would personally probably get a dwarf gourami and some neons.
For the record, also, an African Butterfly fish will not work in a 10g tank either.
Because it seems like you are interested in the less common fish, maybe you could find some killifish that would work (I'm not that well versed in them).