A Minecraft Launcher which is multi-functional, cross-platform
Mangos ZERO is a server for World of Warcraft
Godot is a powerful cross-platform game engine
A complete 3-D game development suite written in Java
You can make it - Open Source MMORPG Platform
Xash3D FWGS engine
A cross-platform PSP emulator
Cross-platform 2D and 3D game engine with modular architecture
Cross-Platform C++ 2D/3D game engine
The main repository for the Linux and Mac OS Bedrock edition Minecraft
An Open Source Minecraft Launcher with Modern UX
Cross-platform rhythm game for the keyboard
Powerful, mature open-source cross-platform game engine for Python
Voxel game-creation platform with easy modding and game creation
A bridge/proxy allowing you to connect to Minecraft
Free and open source real-time strategy game
Cocos simplifies game creation and distribution with Cocos Creator
Open Source MMORPG Framework
The HTML5 Creation Engine
Recreation of the classic Grand Theft Auto III game executable
Stride (formerly Xenko), a free and open-source cross-platform C# game
Tool to statically recompile N64 games into native executables
Cross-platform 2D game engine focused on ultimate productivity
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
The flexible game engine