I'd like to add more African civs, but they were often so politically decentralized that it's hard to find kingdoms that can be included. And those that did exist tend to be the least well-known at that. Hausa? Kanem? Bachwezi? Sure, they might have been important, but nobody's really ever heard of them... Ghana could work. Kongo could work. Zimbabwe is another one, but the Mutapa kingdom would probably better represent that, but Mutapa again just leaves people scratching their heads.