Amelia, In Sound Mind was really fantastic! It's just way more of an indie Steam release than anything else mentioned here which were still market wide pc and console releases. That's why you never hear about it. They needed to get it released to a wider audience which never happened. I do have to say it was perhaps the best indie game I've played. Deserves way more attention!
If only Nintendo could learn to release it's big titles on PC after a few years. Every other game on this list, I believe, is multi platform. Like most games.
I refuse to buy a Switch just to play BOTW. Nintendo needs to learn that the PC market is important alongside consoles. They're the only game company who hasn't learned this.