honey and chocolate gouramis are really pretty, but you would only be able to put 1 in a 10 gallon. there are also neon, ember, black skirt tetras... the list gos on and on with tetras, but be carful some tetras need larger tanks, in fact i would not even recommend the black skirts my self. as for live bearers, there are platys, guppies, endlers and mollies(allot of species get really big though and reqiure large tanks).
as for the 55 gallon, there are SOOOOOO many options, if i were you i would probably go with some cichlids. or if you don't like cichlids here is a cool stocking plan:
10 bleeding heart tetras,
8 neon tetras,
7 bronze or panda corydoras(most active fish i have ever owned),
1 red tailed black skark,
1 pair of blue rams,
10 nerite snails(eventually you would have hundreds though)
5 cherry shrimp,
5 platys,
1 dwarf gourami and 5 tiger barbs.