Low-Tech Mag also discusses insulating the body without electricity: https://solar.lowtechmagazine.com/2011/02/body-insulation-th...

As they mention in that article, the main advantage of synthetics over wool is that synthetics weigh much less while providing the same insulation. However, I figure this is less important if you're sitting around your house than if you're e.g. hiking and have to carry the weight with you, and wool should be great indoors.

Personally I will avoid buying synthetics from now on in an effort to eliminate plastics / fossil fuel products from my life, and reduce microplastic pollution. I will probably be buying more wool, to avoid "death cloth" / clothes that stop insulating if you sweat / get wet.

Are there any other notable natural fibers besides wool that continue to insulate when wet?