Aircraft propeller tachometer - photo

[Toolmaker51]

Reed type resonance meters are still available, one is the Sticht. They also produced handheld cone (RPM) or tire (FPM) driven variety for readings.
BTW/ FWIW there are still operable vintage handheld analog contact tachometers by SW [Stewart-Warner] Starrett, Jaeger and others, reasonably priced.
I wouldn't discount the older non-contact photocell-reflective tape versions either, such as Pioneer.
Sometimes, close to rotating equipment, is too close for comfort.

In midst of setting up kit for electric motor testing; rotation checker, insulation test megger, tachometer, portable ammeters, contact thermometers etc. Personally, threads like this expand range of interests, so posting that array might be worthwhile?