I think the most fascinating mummy is the Iceman, found in the Alps in 1991, because he was an ordinary person who was preserved by a freak of nature.
Ötzi - Wikipedia
Egyptians were ordinary people as well they were preserved in sand albeit not a freak of nature.
But wasn't it mainly royalty that was preserved as mummies in ancient Egypt?
Yes, seriously, how do you have a an ancient coffin and not realize there could be a body in it?