Godot is a powerful cross-platform game engine
The flexible game engine
Solar2D Game Engine main repository (ex Corona SDK)
Fast and lightweight JavaScript game engine built on WebGL and glTF
V1, Mirror Classic. V2, Mirror Engine: Join Discord for access
Flax Engine, multi-platform 3D game engine
Cocos simplifies game creation and distribution with Cocos Creator
Multi-platform 2D and 3D game engine
Cross-platform 2D and 3D game engine with modular architecture
A game engine with an emphasis on real-time cutting-edge solutions
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
JavaScript-based game engine designed to empower developers
Cross-Platform C++ 2D/3D game engine
The PHP Interpreter
An OpenGL RTS game engine written in C
Xash3D FWGS engine
Simple and light-weight 3D game engine
Zig game engine & graphics toolkit
A complete 3-D game development suite written in Java
An unofficial rules engine for the world's greatest card game
Open source voxel game engine with support for survival and crafting
A fully-featured OpenGL and GLFW extension for PHP
Game engine supporting many 3D/2D formats and graphic effects
Unreal Engine Archives Explorer
A game engine powered by python and panda3d