Godot is a powerful cross-platform game engine
Solar2D Game Engine main repository (ex Corona SDK)
Open source voxel game engine with support for survival and crafting
Open source HTML5 game framework that offers WebGL and Canvas
An open-source sandbox tower defense game
Desktop/Android/HTML5/iOS Java game development framework
A certain block game
The game engine for everyone
Voxel game-creation platform with easy modding and game creation
Open source cross-platform multi-purpose game toolkit
RetroArch is a frontend for emulators, game engines and media players.
One framework for creating powerful cross-platform games
A cross-platform PSP emulator
Turn-based survival game set in a post-apocalyptic world.
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Java/JavaFX/Kotlin Game Library (Engine)
Free, cross-platform 2D game engine powered by Haxe and OpenFL
Sandbox video game with a powerful physics engine
Xash3D FWGS engine
Cocos simplifies game creation and distribution with Cocos Creator
Open-source Android/Desktop remake of Civ V
Cross-platform game engine in Rust
The source code to VVVVVV
Satisfying monster shooter
Stream switch games to your PC via USB or network