Yesterday, Valve announced the new beta version of Steam Play that's bundled with Proton, a special version of Wine. Currently, they've whitelisted 27 games previously unavailable on Steam for Linux.
I personally own a few of them. S.T.A.L.K.E.R.: Shadow of Chernobyl works for me without issue. However, the two Mount & Blade games do not launch. I've attached the terminal output. If others have issues launching games on this list, maybe they can post them here.