At the moment I just picked up thronefall, and really enjoy it. It’s great if you like tower defense and city building games, but don’t have too much time on your hands to get invested into longer games. The progression system feels good and adds a lot of replayability. It runs perfectly on Linux as well right out of the box!

I second OpenTTD, it takes a bit to figure it out, but it’s so much fun when you really get the hang of it