Online vendors have made it possible to get most fish.Some of the uncommon fish would include
lyonsi(endangered in the wild)
la ceiba freddys (endangered in the wild)
istlanum (not sure if they are becoming endangered but i know there are becoming harder to get)
grammodes(very rare to see adults)
trimacs(not uncommon but they are just awesome)
veja species (becoming very popular and are real beastly fish) (i love redhead cichlids)
Festaes (Not so uncommon anymore but the most wanted fish among hobbyist)
Loiselli cichlid (parachromis species rule and anyone will tell you they are the top species to keep)
I'M SURE OTHERS CAN ADD TO THIS LIST TO HELP YOU OUT.
Thank you. Ill check all of them out.
Id love to have a pbass. I just sold mine since my plans for a larger tank have been put on hold.