I'm really goi g to go out on a limb here, but there is another one that is as durable, and is also very slick, sheep sherling. For those not knowing what it is, it is a tanned sheep hide with the wool on and cut short. The most common place to find it is on the underneath side of a saddle. Dan Toelke showed me these a few years ago, and I have been using them since then. The advantage is they naturally have lanolin in the wool and leather which makes them slick, and quiet, even when wet.
Thanks,