You could have a Betta, they would love a 10 gallon, snails and ghost shrimp (hopefully the betta wouldn't mind them). Also Betta's are not good with other fish tank mates, so snails and maybe shrimp will be the only options for a betta tank. Correct me if I am wrong. Sometimes people get them to work with other fish, but that is if you have a lot of décor and swimming space.
I think a honey gourami could fit In a 10 gallon, correct me if im wrong.
This is just a list that you could research and pick from, not to add all together:
endler's livebearers
dwarf rasbora
ember tetra's
pygmy cories
dwarf puffer (only 1 or 2, species only)
dwarf African frog (species only)
neon tetra's
guppies