RmlUi - The HTML/CSS User Interface library evolved
Unvanquished is a free and open source FPS/RTS hybrid game powered by the Daemon game engine. Historically based on Tremulous as a continuation with decades of work over it.
Game UI in HTML/CSS for Unreal Engine, rendered off the game thread — RmlUi + QuickJS on a dedicated UI thread. Windows, macOS, Linux, Android and iOS.
X-Ray engine for S.T.A.L.K.E.R.: Shadow of Chernobyl on Vulkan — PC, Nintendo Switch, Android, Linux. Successor of OGSR Engine.