This company is producing a leather alternative and a silk based on spider silk research. I'm not sure about how permie friendly their practices are, but their stuff seems thought-provoking enough to be worth sharing. Hopefully this is the right subforum.
Mycelium grown in corn stalks, compressed and tanned into a leather replacement:
https://boltthreads.com/technology/mylo/
https://thespool.boltthreads.com/2018/04/15/mylo-stella/
Silk based from proteins in spider silk:
https://boltthreads.com/technology/microsilk/
The silk one seems super complicated and some people might not like that one for a number of reasons, though they do say no spiders are harmed making Microsilk. The Mylo Leather stuff seems like something that could be less complicated and much better for the environment than plastic leather alternatives. Perhaps even a permie friendly DIY version of something like this could be something people may want to explore. I just thought it was some really cool stuff!