Freespace 2 is a space combat simulator game from way back in 1999, it may be old, but it has an official open source engine and you should really give it a run.
The Escapists isn’t a game I’ve played before, since the first game isn’t on Linux (yet), but The Escapists: The Walking Dead is now on Linux and our friends at GOG sent me a key.
The full names of the games are 'Al-Qadim: The Genie's Curse' and 'D&D Stronghold: Kingdom Simulator' and they were released on GOG for Linux just before the weekend.
The creepy point-and-click adventure game about a young girl, who is sent off to a mental institution for children after her parents are brutally murdered, has been released DRM free on GOG and on Steam for Linux, and has a new demo.
The first expansion to the engrossing Pillars of Eternity has now launched alongside a massive patch. This is the first part of two planned expansions for the already content-rich RPG.