Hey, not sure if this is the best forum for this, sorry. I've just been thinking a bit about how we might go about making clothes (and other fabric items) after the collapse of civilization. Obviously it won't be as urgent as food, water, shelter, etc. since civilization will leave behind a lot of clothes and fabric to make use of. Nonetheless, I think it's worth learning about some (ideally vegan) ways we can produce clothes without murdering the environment and relying on slave labor.
There are a couple fibers that I think should be able to fulfill most of our needs in most places: hemp, flax (linen), and cotton. Climates similar to my own (temperate with cold winters and hot summers) could use hemp (to make canvas for durable, warm outerwear) and linen (for undergarments and light, breathable summer clothes). These days, canvas is usually made from cotton but I suspect hemp (which was used historically) would be preferable post-collapse outside of tropical and subtropical regions since cotton grows best in warm climates and hemp is super hardy. Plus certain strains of varying legality could be dual purpose. Linen meanwhile, is a lot more labor intensive to make, but also cooler, more breathable, and more comfortable on your junk.
For additional warmth, winter outerwear could be lined with some sort of insulator (maybe leaves?).
People in warmer climates could rely more on cotton, since it grows well there and is pretty cool, breathable, and versatile.
Of course, as climate change continues, these climate-specific ideas will probably become less accurate. By the time this information is actually relevant, it could be totally outdated.
Of course, there are also some non-vegan options. I don't think these would really be necessary in most places, but polar regions without much vegetation might need them. Wool could be very useful, but I think in such polar climates buckskin would be even better. It's relatively simple to process, warm, and durable, as attested by its historical importance to many indigenous peoples of North America. Furs of various animals are also an option. Leather could be used too, but requires much more processing.
What do y'all think? This is only really based on pretty cursory research so I could be totally wrong about a lot of things.