I always like endlers, I actually need to get some again. I'm in the same boat as you, Boven. I have a Petsmart near me and then a couple of mom & pop stores, but it's still not easy finding what I want (endlers, for instance

), and healthy stock on top of that. Oddly, though, Petsmart had tiger mickeymouse platies... that was a find, but I had to put off buying them.
A dwarf cray (or maybe a trio?) would be neat, especially in a uniquely shaped tank. I don't know where you are located, but you would almost definitely have to purchase them online, if you really want them. I think smaller tetras might not mind the dimensions... like flame tetras, or some dwarf rasboras if you're lucky to find them local. Anyway... cories are always enjoyable in any tank.