I saw you other post. Do you have a 20g long (30 x 12 x12) or a standard 24 x 15 x ? That can make a difference in what fish you can easily stock. I'm glad you don't want GF, your tank is too small.
I like small bottom fish like any of the dwarf corydoras (so cute!) & smaller rasboras OR smaller tetras. What fish are you interested in? We can help you decide, give us an idea on what fish you like.