Archaeologists have found now now well-known paintings comparing Egyptians with other peoples surrounding them. This one, of a Libyan, a Nubian, an Asiatic, and an Egyptian, is probably most famous.
A somewhat more interesting set can be found on The Enemies of Ancient Egypt page.
I had to work to find a neutral page to cite. The majority of top hits on Google Images go to white supremacist sites belligerently opposed to afrocentic theories. Those guys are diligent, admittedly, but I don’t want to up their hit count.
We also know that a large number of black tribal peoples now found along the fringes of the Sahara were pushed south when the climate turned drier and the desert rapidly spread. They would have been in today’s North Africa but not along the Mediterranean itself.