Desktop/Android/HTML5/iOS Java game development framework
Satisfying monster shooter
Java/JavaFX/Kotlin Game Library (Engine)
KorGE Game Engine. Multiplatform Kotlin Game Engine & Korlibs
Open source HTML5 game framework that offers WebGL and Canvas
Open-source engine for Heroes of Might and Magic III
The game engine for everyone
UCI chess engine
Cross-Platform C++ 2D/3D game engine
An open source reimplementation of the Among Us Server
Netcode that provides networking capabilities to GameObject workflows
Solar2D Game Engine main repository (ex Corona SDK)
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Cross-platform game engine in Rust
Home theater software and entertainment hub for digital media
One framework for creating powerful cross-platform games
Accuracy-focused XNA4 reimplementation for open platforms
Kotlin extensions for the libGDX game framework
A completely free, open-source, 2D game engine
Action-adventure game originally released in 2013
Gideros Release version
A MUD client for Android, iOS, Linux, Mac OS X and Windows
3D modeler, 3D game maker, 3D demo maker
... the open-source glide computer