Micarta was the first thought that popped to mind, but here's a very slightly more in depth take:
My very simple needs in a knife handle material all revolve around it being durable, comfortable and perhaps most important; non-slippery even when bloody, oily, sweaty, gunky, dry, under high or low torque, etc. Also, I'm quite convinced that every single fixed blade knife ought to have some means of protecting the user from inadvertently sliding forward onto the edge or backwards off the handle.
It's because of those very simple criteria that I really, really like simple molded plastic handles on kitchen knives, and contoured Micarta handles on 'nicer' stuff. I'm sorta ambivalent about Kraton(tm) and the other myriad of soft synthetics, but one thing is certain. I don't buy knives based on how the handle "looks". There's far too much effort wasted by way too many folks getting terribly designed handles to 'look' good. I don't care how it looks. I care how it performs.
That's my ELU opinion anyway.