"WEll I don't know what subsaharan-African groups were famous in the ancient world other than Cushites (in what is now Sudan), Zanzibar'S INHABITANTS and Ethiopians Both groups extended marginally imporant empires during ancient. By the Middle Ages and modern times the Cushites were pretty obscure."
How exactly DOES a group become "famous"? I assume you are referring to how many times they are mentioned in European and/or Mediterranean literature. There's three problem with that premise. 1, the groups further south would've naturally & obiviously been harder to reach than those further north. 2. Records of African contributions almost unanimously seem to disappear when hostile outsiders appear. 3. How many times do the West African empires, for example, mention contributions made by those north of the Mediterranean?