Many beanies currently are made of synthetic fibres, usually acrylic (= polyacrylic), or polyester, or a blend of the two. This is great because these are not from animals.
For a while I've been looking for one that's made from 100% cotton or hemp (or a blend).
Well, ... check out this beanie:
I would call this a late 1990s Jamie Thomas beanie - by the French skateboard wheel company par excellence "Haze Wheels".
Note that the fold-over beanies (= cuffed beanies) by Haze Wheels contain sheep's wool. (There was some incorrect info on their website saying one of the fold-over beanie was 100% cotton - this is not correct.)
You can follow Haze Wheels on instagram ... if you're inclined to take part in the demoniacal system that is instagram. Just click follow, log out, and go skate.
Side note: Many beanies also have wool (from sheep), but I don't use wool because animals can be hurt when they are sheared. Shearing itself doesn’t necessarily harm sheep, but in large-scale or rushed operations, animals can be injured or stressed.
And where do "farmed animals" (of any kind) usually end up before they get very old? The slaughterhouse. Of course, technically, you can obtain animal hair from an animal of you happen to be friends with that animal, say you have a rescued sheep in your garden/sheep stable. But I don't.
Check out this BBC article of PETA being criticized for exaggerating that wool is as bad as fur. Sometimes it maybe, sometimes not. But even if it's not as cruel as fur, that doesn't make it animal-friendly.
In the BBC article, the the Advertising Standards Authority (ASA) is quoted as saying "that sheep were not killed for their wool as animals were in the fur industry, and there were 'standards in place' for their general welfare."

