Cocos simplifies game creation and distribution with Cocos Creator
Voxel game-creation platform with easy modding and game creation
Multi-platform 2D and 3D game engine
Open-source Android/Desktop remake of Civ V
A certain block game
A cross-platform PSP emulator
Stream switch games to your PC via USB or network
UCI chess engine
The game engine for everyone
Desktop/Android/HTML5/iOS Java game development framework
Home theater software and entertainment hub for digital media
Free, cross-platform 2D game engine powered by Haxe and OpenFL
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Godot Kotlin JVM Module
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
SDL library for Android, including several games.
3D Engine c++
GameServer is a sophisticated, game server designed for online games
GemRB is a portable open-source implementation of the Infinity Engine
GLScene Engine for Delphi & C++Builder VCL Windows 32/64
Android, UIQ 3.0, Series 60 Edition 5 open-source software
computer opponent for the board game Blokus
3D modeler, 3D game maker, 3D demo maker
... the open-source glide computer