fheroes2 is a recreation of Heroes of Might and Magic II game engine
Skin changer for League of Legends (LOL)
Open Source MMORPG Framework
Rcon client for Minecraft
Powerful, mature open-source cross-platform game engine for Python
Unity / XNA game patcher and plugin framework
3D game engine/framework in C, with Luajit and Python bindings now
Unreal Engine Archives Explorer
Traditional roguelike game with pixel-art graphics
Desktop/Android/HTML5/iOS Java game development framework
Custom launcher to manage multiple installations of Minecraft at once
lua dev plugin for unreal engine 4 or 5
Cross-Platform C++ 2D/3D game engine
Noob-proof (N)3DS Custom Firmware
Voxel game-creation platform with easy modding and game creation
One framework for creating powerful cross-platform games
Jazz² Resurrection: Open-source reimplementation of Jazz Jackrabbit 2
An open source re-implementation of Chris Sawyer's Locomotion
A lightweight game server framework implemented with Actor Model
Map Pixel Art Generator for Minecraft
Library for Switch Homebrew
Cocos simplifies game creation and distribution with Cocos Creator
Open source clone of the Age of Empires II engine
Blockchain in C#/.NET for on-chain, decentralized gaming
Descent 3 by Outrage Entertainment