https://www.cnet.com/news/e3-2018-games-you-can-play-right-now/

Most of them are PC-based, and yes, some of them had already been announced or even been on sale, but all of them have some significant changes that makes them fresh and new(ish).

Quake Champions has been available in beta for Steam for some time, but Bethesda announced it's now free to play if you sign up before June 17. If you ever played the original Quake 3 Arena, you'll know what you're getting: intense death-match maps, rocket jumps and plenty of gory gibs. Quake Champions received a lukewarm reception when it first appeared, perhaps because it followed too closely behind Doom without adding any significant gameplay improvements. But you should get it now because it's much better, and hey, it's free!