I think a Congo-style planted layout would look really cool, with pale biege sand for the substrate, and rocks and bogwood. And for plants Anubias, Bolbibits and Nymphaea would look awesome. And although it's not African, a bit of Cyperus helferi and some Java ferns and Crypts added in would look nice too. And for fish a large shoal of Alestopetersius caudalis would be stunning! And you could also add a few pairs of Pelvicachromis taeniatus