I wish I had that tank!! Too many options!
Depends if you want to go a few big fish or a LOT of little fish, aggressive, semi, peaceful.......
South American theme: Discus or Angels as the centerpiece school with a few large schools of tetras, a big shoal of cories, & maybe a couple plecos (maybe not the best choice with discus?) or a ton of otos?
Africans cichilds?
Asian theme: barbs, gourami(s), loaches, danios, rasboras, & SAE???
(my posts are starting to be All like this........ time to lurk)