I wouldn't keep dwarf gourami in a 10 gallon, but some members have with success. I'd have to look more into it.
Scarlet badis, bettas, sparkling gourami, multifasciatus cichlids, pea puffers, endlers and many more come to mind, but they need different types of water. Do you know your gH?
There are some really beautiful strains of guppies available these days. They are very easy to breed if you want to do that...they'll figure out how to do it all by themselves.They're always busy and very curious so there's plenty to look at. They're hardy and only require simple management in a clean, cycled tank and make a good choice if you want a small fish that will give you a lot of pleasure with low maintenance.