>>1991487Merino underwear and wool socks are functional. Everything else is fashion or fetishism.
But that's what we're here for, so dig in:
Midlayers like wool sweaters or shirts are comfy, if heavy. Shirts provide some wind protection in case they're worn without shell, which makes them nice for work outdoors. Sweaters on the other hand (loosely knit ones) have great breathability and actually not that much insulation if not covered on top. If you're overheating you can drop or open your shell and cool down quickly, without being exposed directly to cold air.
Shirts are pretty common in america so I won't comment on that; in europe the only reasonably priced ones I know are the bison bushcraft shirts and the edvardson vadmal one. Varusteleka makes recycled wool blend ones; I'll leave it to you whether you want that. Sweaters are everywhere. Commando sweaters are nice and cheap.
Wool shells are usually felted wool (melton, vadmal, loden). It is wind repellent, water repellent (if lanolized), insulating, breathable. Historical people used it for lack of alternatives, hunters still use it for being silent. This fabric is expensive and the garments made from them are even more expensive (than they need to be). You can find surplus at a tenth of the price it would cost new (though not very often anymore...) Look for the fabric weight: 300g/m2 is the lower limit for lighter jackets or trousers, 500g/m2 upwards is winter weight. There are lots of overpriced offerings here, so I'll just list the cheapest ones I know (note, all of those use 100% new wool loden, they didn't cheap out on the fabric): Varusteleka sells "blanket" shirts, loden friedl sells a nice light jacket, hedlund sells more substantial jackets, bekla sells trousers.
