One larger gourami (opaline, blue, pearl ??), 3 smaller corys OR 2 kuhlii loach, 3 mid sized tetras or rasporas...and LOTS of Tall plants in the back half area and a nice thin taller piece of driftwood...that doesn't take up too much floor room. For plants go with low light plants...then you won't have to worry too much about lighting and all that. (Java fern, java moss, anubias, most cryptocyrenes, water sprite)
Have a good substrate for plants...onyx sand or echo-complete for planted aquarium or a mix of both. They're both a black colored substrate if you prefer that. Or flourite or flora base for a brownish color substrate.
I have a 20 hex sitting around myself that I'm pondering what to do with...this here is just one of the ideas I had thought I might try with it.