I’m surprised to see you’ve got no response here yet. Cables are a great subject for DIY.
Ordinary copper or even copper coated aluminium (CCA) is great for patch cables. For flexibility I recommend thinner wire and silicone insulation. For high durability, 20awg or thicker is fine. I touched on this topic here, mostly from the viewpoint of single core banana cables, but the basic ideas translate well to more conventional dual core cables. For my DIY banana cables I keep a big reel of 14awg dual core speaker cable which I split into single core and then making up the cable is a two minute job because you just strip the ends and screw a banana plug on each end.