If its in the fish room and you enjoy breeding pair activity dovii or umbee would be fine. If its your main viewing tank a community may give you a lot more enjoyment. SA would give you a nice relaxing setup and you could have a lot of fish. CA would be more active.
I would do the below if it was my setup and my main tank.
Black aro
Flag tail
Wide bar silver dollars
Atabapo severum pair
Psittacus pair
Geophagus winemilleri group
Some type of acara
Decent sized catfish or ray.
Just my preference.