Well theres tetras, barbs, rainbow fish, rasboros and all knids of other fish that could fit that bill, which types of fish do you like?
A personal favourite of mine are congo tetras which look great in a shoal of 7 or more fish and get to around 3 1/2" long (adult male size). Silver dollars also make a nice display but have the drawback of being plant eaters and tiger barbs can look stunning but limit possible tankmates through aggresive nippy behaviour.