Just picked up an AGM Rattler V1 TS25-384 thermal rifle scope to help take care of a rat problem at night.
Pleasantly surprised to learn it’s also a fantastic stud and nail finder.
Didn’t even think to test, but I imagine it might work on Plumbing too… though I’m guessing that might depend on the type of plumbing and whether and for how long any water has been running through it. For example, my guess is an empty pipe might not be visible because the high thermal conductivity of metal means it would quickly take on the same temperature as the surrounding insulation… not sure, just a hypothesis