The weirdest tool I own is also one of the most useful (and it's $10 on Amazon)

I have a number of inspection cameras, and they're fantastic for getting eyes into places that you normally can't get to. But they're typically large and bulky, designed for mechanics and HVAC engineers, which limits their usability when it comes to inspecting device ports or probing around cracks and crevices looking for a lost fastener.

Also: I replaced my MacBook charger with this compact wall unit - and wish I'd done it sooner

In my quest to find a small, portable, low-cost camera for confined spaces, I found this one from Amazon, designed specifically to inspect ear canals. 

Although that is its advertised purpose, this tiny 1080p HD camera can be used for a variety of tech needs. I'm not a doctor so I'm not going to be recommending ...