So that's 500 games, that aren't supported by the developer on Linux that should for the most part be click and play from within the Steam client on Linux. If we include games trending towards a Platinum rating, it's even higher at 569. That's pretty impressive considering Steam Play hasn't been out for too long. It's worth mentioning though of course, that Wine has been around for a long time.
This list of 500 games includes titles like Call of Duty 4: Modern Warfare, DRAGON BALL XENOVERSE, Heat Signature, Shadow Warrior 2, Outlast 2, Hitman 2: Silent Assassin, Red Faction Guerrilla Steam Edition and a lot more interesting titles.
Even so, a lot of this comes down to the vast improvements coming in quickly to the DXVK project which had 28 releases last year and it's not even finished yet. Most recently, DXVK gained improvements to fix issues with FIFA 19 so Football fans will probably enjoy the next DXVK release (and so the Steam Play version that pulls in the update).
I will keep an eye on it and see how the ratings change across this year. Regardless of how some feel about Steam Play, I do think it was a very smart move from Valve and look forward to following the progress. I still have reservations about the short-term and long-term impact of it but Linux gaming simply wouldn't go anywhere with 3-4 AAA releases supported a year and it's far more enticing for users to use Linux if their current games work.