First up looks to be Yakuza 0, which you can pre-purchase right now on Steam for $17.99 (USD) with a 10% discount. This one will be released on August 1, 2018. As you may recall, I kind of really loved Yakuza 0. I'm sure I'll love it even more with an uncapped framerate and the option to go up to 4K... on my 1080p monitor.
Yakuza Kiwami is also headed to Steam. You are not yet able to pre-purchase Kiwami nor is there a release date set for Kiwami through Steam. We also reviewed Kiwami too.
There is no word yet on whether or not the upcoming Yakuza Kiwami 2 will be released on Steam in addition to its PS4 release. There is also no word as to whether or not we will see the recently released Yakuza 6 or the just announced PS4 remasters of Yakuza 3, Yakuza 4, and Yakuza 5.