Do you have one? Or maybe a few? Or do you have a favorite technique? The one I personally use most often is the trachea grab. Most commonly known as the eagle claw to the throat. Not very impressive to watch, but it works on pretty much everyone. My second most used is the shadowless kick. It's quick, and sneaky. When sparing, my partners almost never notice me doing it. One of my teachers has a front kick to round kick combo that he likes. And he's very good at it. And another teacher of mine has a move he uses all the time. It doesn't have a name, and is hard to describe, but it gets you moving one direction then switches to throw you down with a wristlock.