When you make scales for restores or custom scales for people what is your favorite material to work with and which one do you just cringe and consider taking off your list of materials to use?

I currently have only worked with wood and printed circuit boards. I have seen the threads on horn so will stay away from that for a while but am looking for other materials to make unique and interesting scales as well as making more classical looking ones as well for my personal growing stable of straights.