One fish that is pretty nice to watch is the Microdevario Kubotai. Around here they are about $5. each, I only have 5. Planning on more but they are good movers around the tank and bright. There should be a better group of them in my tank (very soon).
A nice little bottom fish is the Peacock Gudgeon.
Rams are beautiful - I love the Blue Rams.
IF you aren't interested in having CO2
, and just want to kick it with normal lighting, some great low light plants are many (most) Crypts, Anubias - nana is awesome (not Pinto), Bolbitis heudelotii. I haven't yet started growing them but lots of Bucephlandras are lower light tolerant.
What about the focus of the tank on planting and Aquascaping?
Are you looking for a challenging option or a easy soothing option, or.....??? Do you have time and money for a fancy high tech tank, are you able to deal with the exacting adjustments, and lots of algae and dialing in the parameters?
Simple and beautiful Neons or Cardinals and Cory Cats, Glass Cats. Lower light plants.