I actually have a small lot of the Teensy boards for a USB hardware hacking project I was running for a while. For example, I used them to emulate a USB keyboard to automatically press 1, 2, 3, 4, 5 in Path of Exile over and over to avoid wrist strain during a time in that game where every player needed to constantly hit those keys in a loop to play at decently high levels.

These boards were an endless nightmare to work with. I had to cycle through many different USB controllers and it was really more like voodoo. I tried buying a few boards from different suppliers and every board had the same voodoo so I gave up and moved on.

I ended up getting ATtiny85 to work for what I wanted which sucked too, but at least it worked and was a fraction of the price so I could actually send them to all my friends.