A few of my favourites are
Standalone or 'in pairs/trios' fish:
Rams
Apistos
Keyhole cichlids
Angel fish
Firemouth cichlids
Pearl gouramis
Honey gourami
Paradise fish
Bettas
Wild-type bettas (if you can get your hands on them)
Clown panaque
Bristlenose plecos
Shoaling species:
Corydoras (so many different species to choose from! My personal favourites are Sterbai and Schwartzi)
Hatchetfish (interestingly shaped and active, one of my favourite characins. They will stick only to the top, and make sure you have a tightly fitting lid!)
Rainbow fish (I like the reds and the threadfins)
Rummynose tetras
Lemon tetras
Glass catfish
Von Rio tetras
Black or red phantom tetras
Glowlight danios
Oddballs:
African butterfly fish
Ctenopoma (both the Ornate, and the Spotted Leaf)
Invertebrates:
Nerite snails
Ghost shrimp
Obviously not all of these guys are compatible - some are community, some are hardier than others, and some are die-hard predators, but this is just a small list to start some research and see what kind of tank you think you'd like to make.