In about 1963-64 I worked in a business school which still taught Comptometer. Even then I never saw one used in an actual business.

How about Syquest drives for computer storage? I have a working set of two...set up for Windows 3.1. I 'think' I still have the drivers for Win 95. (It is a skuzzy (SCSI) setup...lots of cables and 'stops' for ends of cables. Yes, I still have a working 3.1 machine... but with a non-working mouse)