Here's my idea: skip the ordinary stuff. Leave out the neons and the
Corydoras paleatus. Instead, look to unusual species of tetra and catfish. How about the emperor tetra
Nematobrycon palmeri or the blue emperor tetra
Inpaichthys kerri? Both no more difficult to keep than neons, but rather more active and colourful in a different sort of way. Similar, try a more unusual species of
Corydoras, perhaps
Corydoras panda or
Corydoras julii?
This way, you're not just going with "oddballs" but species of regular stuff that people just don't keep all that often.
Alternatively, I'd heartily recommend getting a school of South American puffers plus some catfish and perhaps tetras compatible with them.
SAPs look amazing as a group, and unlike some other oddballs they're neither drab nor retiring. Indeed, it's hard to think of a single freshwater fish that matches them in sheer energy!
I keep mine with a variety of fish, but the ideal tankmates seem to be
Synodontis and fast
Hyphessobrycon such as
H. erythrostigma. SAPs seem to ignore robust loricariids, too.
Cheers, Neale