My work boot socks are Kirkland brand Merino and I’ve bought some Smartwool socks. This is not a recommendation of those brands, just the easiest one’s to find with a reliable amount of wool when I bought them. They’re both ok, but really any sock with a sufficient amount of wool in the blend and a good fit will work. The one’s with more wool and less stretch will obviously not stretch as much, but they will eventually confirm to your foot shape surprisingly well. The one’s with less wool in the blend also seem to not last as long. If you’re wearing them in a boot and expect some actually dirt getting in there, a thicker sock will hold up better and protect your feet better long term. At least that is my impression.