This is a really rough one have / had so many cool fish so I'll go with the top 5: Hypseclera Temparalis (chocolate cichlid), Uaru, Oscars, Labeotropheus Fuelleborni, Angels
Flashy/colorful top picks: Killifish, Discus, Guppies, Peacocks and Haplochromis sps
Ugly can't really pick one since what...