I'm allergic to polyester and most anything made of plastic. I get painful open sores, and hideously itchy. It is difficult to find clothes at best.
Plastic is snuck in more shit than you'd think. Often unlabelled. More than one pair of pants/shorts I've had to ditch/edit because the pockets were polyester or nylon in a "100% cotton" garment. Drawstrings are bad for this, too. And waistbands.
Seems to be weirdly common to be adverse to plastic-based fabrics in autistic communities.
I most often wear:
cotton/linen/canvas/denim
rayon/bamboo (plant based, do need to be a bit careful because people fake it, very loose "swishy" fabric)
hemp
real leather ("vegan leather" is literally plastic and i will fight people greenwashing calling it "vegan" and not the awful pleather it is.) (very difficult to find coats without nylon linings though.)