At the release of the Crusader Kings III: All Under Heaven expansion and free update, the Linux and macOS versions were problematic but it should now be fixed.
Monado is an impressive open source XR runtime that aims to support a whole lot of hardware, with a focus on great Linux support and version 25.1.0 is out now.
Dungeons of DUSK has been announced from New Blood Interactive. It's a retro dungeon crawler set canonically between the episodes of the classic FPS DUSK.
The developer team at Discord released a new engineering blog post yesterday (December 8th) detailing lots of fixes, along with some Linux improvements.
Developer team EMINOMA have officially rebranded Team Fortress 2 Classic into Team Fortress 2 Classified, and they've set a release date for January 30th.
Framework Computer BV have announced a nice big expansion of their sponsorship program with many open source events and Linux distributions benefiting from it.