This webpage has a fairly comprehensive list of all body parts that are now useless. Some time in our evolutionary past, they were useful, but are now just sitting around, waiting for evolution to get rid of them. For example:
ERECTOR PILI:
Bundles of smooth muscle fibers allow animals to puff up their fur for insulation or to intimidate others. Humans retain this ability (goose bumps are the indicator) but have obviously lost most of the fur.
See full article. Blogging about it because some things you just need to know for no good reason…