There's one game I always keep installed, and that's "Half-Life 2".
I've played it since it was released and I didn't even have an internet connection, and I still play the game fairly often.
I also have the Black Mesa mod, I began using it when it was free, and decided to buy it when they changed it to a paid version... -but I usually prefer HL 2 (and the two episodes)
Other than that, I mostly play "Battlefield V" online with a friend. It's not all that great, but it is great for gaming a little with a freind and talking a bit about this and that.
I recently received "Transport Fever 2" as a gift, which I also enjoy, it reminds me of "Transport Tycoon" which I used to play in DOS many years ago, and had a lot of fun spending time on.
I'm considering trying to get into "Control". I saw a review somewhere in which Twin Peaks was mentioned as a reference. Being a big Twin Peaks fan, I'm thinking I have to check out Control - luckily it was free with my graphics card. I just need to find some spare time