The list I have probably doesn't have the correct ammount countries, empires, and kingdoms. Please tell me if you find any missing countries
1) Consider adding ancient empires (Rome, Carthage and various caliphates) that controlled parts of Africa;
2) Consider African empires that controlled parts of Africa (Mali, Songhai, Kongo, Zimbabwe etc);
3) Perhaps where a country controlled only part of a country, indicate this. For example, the Netherlands only controlled a small part of south-western South Africa, not the whole country;
4) 99% certain Norway never controlled any part of South Africa (I am South African). If you have more info on this though I would love to learn about it.
Great idea for a quiz, well done!