I'm not a Cory fan either, prefer Synodontis and pleco's. One good option for your relatively small hex tank would be Akysis catfish. You aren't likely to find them in an lfs
, but they are available online occasionally. They look similar to bumblebee cats (like a mini bullhead) but only grow to around 2.5". They're fine alone or in groups, neither particularly social or territorial, and too small to eat anything bigger than small fry.
Otherwise, a BN pleco would be helpful for algae after the tank is established. Most of the really eye-catching pleco's are nocturnal, generally about as visible as your SA bumblebees.
One other catfish that comes to mind is the whiptail. There are a handful of different species, but they're all very mellow fish that don't bother anything or seem to be noticed much by other fish.