Cross-platform 2D and 3D game engine with modular architecture
Cocos simplifies game creation and distribution with Cocos Creator
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Cross-Platform C++ 2D/3D game engine
A free/open source client and automation tool for Ragnarok Online
Cross-platform, open source, and super fast MUD client with scripting
Free game engine for development of desktop, mobile, and web games
Voxel game-creation platform with easy modding and game creation
Source code repository of the FreeOrion project
A lightweight game server framework implemented with Actor Model
Open source clone of the Age of Empires II engine
3D game engine with lua scripting
Botcraft is a cross-platform C++ library to create bots
FlightGear Flight Simulator: free open-source multiplatform flight sim
3D modeler, 3D game maker, 3D demo maker
MIT Licensed Open Source version of Torque3D from GarageGames
3D C++ Game Engine - yet another open source game engine
2D Game Engine
A lightweight, fast and extensible game server for Minecraft
The Atomic Game Engine is a multi-platform 2D and 3D engine
Open Game Bootstrap
Gorgon Game Engine (GGE) is a C++ game engine that handles many tasks.
cross-platform 2d game engine