I'd honestly just hold onto them for at least a few months and periodically post on various forums and Reddit to see if the rightful owner can be found.

If anyone tries to claim them it should be fairly easy to verify if they are the rightful owner by asking them the names of at least 10-15 of them.

Also contact the police of nearby counties as well, your own county's police is probably too lazy to see if there is a theft case elsewhwere in the state.

Also dig through them to see if there are any notes, in case any of them might have been gifts, there might be some clues as to who the rightful owner is.