I did not know these were a thing!
PS I love these insoles, if the ones you buy don't have natural lining. You can also find wool socks and those will wick away moisture and keep your feet from getting cold https://www.amazon.com/gp/aw/d/B01BOV3ROO
Discussion
They're so a thing! There might be other brands of wool insoles, I personally never looked around after I got these bc they had the arch support I needed, but if you don't want that, there are likely others.