Technical fabrics, inventive high utility designs and mods. But that doesn't necessarily mean new.

Basic wool socks will probably the best upgrade you can make. It’ll eliminate stinky feet, stinky socks, and stinky shoes, and the sweat is absorbed. Very technical for the price. I got mine from some Vermont company called Darn Tough and they’ll replace your socks for free if they ever get damaged. They also have them at Costco in larger packs.