These are just some of my favourites.
Tetras - cardinal, glowlight, pristella, rummynose, black widow, serpae, longfin minor.
Barbs - cherry, tiger, chili.
Gouramis - honey, blue, dwarf, maybe pearl?
Loaches! - kuhli, Pakistani.
Obviously not all of these at once, especially since some are totally incompatible, but they are some ideas. :)