Not sure what sort of tank size, water params, availability, price range, etc you're looking for but:
Rasbora / related
- Rasbora kalochroma : Clown Rasbora
- Trigonostigma hengeli : Smaller and more colorful than Harlequin rasboras
- Trigonostigma espei : Even smaller than abvoe
- Boraras maculatus :
Nice pic here Very small!
Tetras
- Hemigrammus erythrozonus - glowlight tetra
- Paracheirodon axelrodi - Cardinal tetra
- Hemigrammus rhodostomus - Rummy nosed tetra
Danios:
- Danio choprae - Glowlight danio
- Celestichthys margaritatus - Celestial Pearl Danio (I don't recommend these, they're endangered b/c of the aquarium trade)
Also avoid: Puntius denisonii (Redlined torpedo barb) unless you know it's captive bred. Very expensive anyway.
Some other fish:
- A few species of Apistogramma including: (these are SA dwarf cichlids)
A. cacatuoides
A. mcmasteri
A. agassizii
There is also the "orange laser" var. of Corydoras.
There may also be some species of killifish that would be acceptable in a community tank, but I'm not an expert on those. Also, there should be some rainbow fish that could work (but rainbows require larger tanks)
*Edited to add fish and reorganize my messy post