While not classic test equipment but it sort of is.....
I recently bought a Qark Shockwiz - a Bluetooth pressure sensor system that you temporarily connect to your mountain bike fork or rear shock via the air connection. You then go for a ride and it records pressure data and can make pretty good suggestions on adjustments to your fork/shock.
For those not caught by the mountain bike craze - the parameters available are, pressure, presence of spacers (tokens) to alter the non-linearity of pressure ramping with compression, and both high and low speed compression and rebound settings.
Everything gets filthy and you should service the shock - which needs a 32mm socket with no taper at the entrance - of course Fox sell one, $50 aus, so I bought a cheapo and ground it flat😁
Photos of the Wiz, the app and the bodged socket.