Oh but there are! I can't speak to African-Persians or African-Chinese but there very much descendants of African peoples in the Arabian peninsula and various Arabic-speaking countries particularly in Yemen and Oman where there was a good deal of exchange between these populations but elsewhere as well. As, indeed, there are still a large population of ethnic Arabs in places like Mombasa, and as there were in Zanzibar and along the Swahili coast until the late 20th century, when, for various reasons, up to and including including mass violence, some of those populations declined.

Someone asked this question a few months ago, and it generated a fair amount of discussion