This is interesting: Sky RC brushless motor checker

[BrianG]

It's probably just a basic ESC with HE sensors/shunts on each phase to take the various readings with current limiting for potentially bad motors.

I like how the label includes motor "break-in" as a feature.

Something like that would be nice to see if you have a partially (or fully) burnt phase without risking ESCs...

It would have been nice if it accepted standard 12v power source though. Looks like it was meant to power it via 2s lipo. But being rated for a max of 18A, I don't think that standard crappy power jack is meant for much beyond 7-10A.