The closest I get to man-made materials are my crocs and my rainboots.
Yeah, at least my crocs can breathe, and they sometimes need to!! But they are great when I'm refinishing furniture on a hard concrete floor. Much easier on my back. But other than that, I try and stay away from stores that smell like plastics at the door!
(Although I confess to making the occassional Payless forage when I'm back in The New World, for a summer colour sandal hit!)