You Can Play Over 2,600 Windows Games on Linux Via Steam Play (tomshardware.com)
At the end of August, Valve announced a new version of Steam Play for Linux that included Proton, a WINE fork that made many Windows games, including more recent ones ,such as Witcher 3, Dark Souls 3 and Dishonored, playable on Linux. Just two months later, ProtonDB says there are over 2,600 Windows games that users can play on Linux, and the number is rapidly growing daily. From a report: When Valve Software launched Steam Play with Proton, it made it easier for gamers to play Windows games that hadn't yet been ported to Linux with the click of a button. Not all games may run perfectly on Linux, but that's also often the case with Windows 10, which can not play older games as well as previous versions of Windows did, even under Compatibility Mode. In only two months, the database of games that work with Proton has increased to over 2,600 -- more than half of the 5,000 Linux-native games that can be obtained through the Steam store.
For those that want to look at the ProtonDB site.
https://www.protondb.com/
For those labouring under the assumption that these counts are inflated with crappy games, I collected some stats on the 4500 best games on Steam. These are the ones that Steam flags as "Very Positive" or "Overwhelmingly Positive" based on aggregated reviews. Of those, 1500 are supported natively on Linux and another 1500 are playable without much trouble in Proton. It's also become clear that most of the reports being submitted to ProtonDB are for the better, well-known games. Hardly anyone is submitting reports on the crappy shovelware games.