Mine is a random forehand slice in which I just make a low slice as hard as I can just before it reaches the ground. It usually goes really high and close to the lines and just literally bounces to the left of my opponent. Sometimes it really trips them out when it bounces with that spin.
My co-unique shot is the aggressive backhand slice and onehanded backhand slice down the line. Usually I play two handed, but I've learned to slice it really hard down the line when the opponent is way out of the court, they can't get to that shit. The other aggressive slice I channel it from any frustration I experience and hit it literally as a rage shot. When it passes the net, the ball commits suicide and doesn't bounce more than a couple inches off the court. Whenever it comes on it usually goes really deep, when it goes into the net it adds to the frustration which fuels my next attempt.
Worthy mention; When an opponent moonballs to my forehand side I slice it as high as I could reach which ends up being a wide dropshot in the service box. I usually trick people thinking I'm going to smash it hard.