I definetly want a gourami.If youre not a fan of tiny fish then youll have to upgrade from a 10 gallon as only tiny fish are suitable for a tiny tank.
You COULD do a Dwarf Gourami and a small school of Rasbora Hets. My son has a 10 gallon setup with those and its a fun tank.
There are a lot of options for a 10 gallon but again, youll be limited to tiny fish, and just because the fish is tiny doesnt mean a 10 is suitable. Some tiny fish really need room to swim, so a 10 is too small still.