Mostly they are called thrust washers because that is their function in that given application. They might be something more than an ordinary washer though, either a specific diameter or thickness, or they might have a ground finish, or they might be made of bronze for example. They might even have an oil groove on the face(s), like the long spiral groove you sometimes see in internal bores of plain bearings. No reason why you can't turn your own up, provided the material and finish is right for the job in hand.
Edited By Steve Pavey on 06/11/2015 10:25:37