TIL (thing I learned)
Had a user upgrade to macOS 10.14.1 and no printers showed up anymore.
So using my Google fu I found some posts (see one below) which described a novel way to reset the print queue on macOS. An old trick apparently. Learn something new everyday.
A quick trip to a terminal and it worked! The existing printers returned to System Preferences and printing resumed.
$ cancel -a
DAM SAN 