And they don’t have to be old either. I have had very good experiences selling recent and older yearbooks.
High school and college yearbooks are equally as valuable. Even jr. high and elementary school editions have a market.
Before you list any yearbook, do some research on the internet for any famous alumni that may have graduated from the school. If someone is in the there that is famous, it can substantially raise the value of the book, depending on who it is. In college yearbooks, look for any famous bands or entertainers that may have performed there, as that can also be a great selling point.