Try Buffalo Arms they have some that I have used in fiber and cork -
https://www.buffaloarms.com/
My other favorite is Durofelt and I will use 2 - 1/4" wads and dip them in SPG or another type of lube for brass shotshells. For muzzleloading shotguns I only use 1 - 1/4" wad, but lube that as well -
http://www.durofelt.com/image_26.html