Godot is a powerful cross-platform game engine
A simple and easy-to-use library to enjoy videogames programming
Enables Roblox developers to use professional software tools
One framework for creating powerful cross-platform games
Desktop/Android/HTML5/iOS Java game development framework
Real Time Strategy game engine supporting early Westwood classics
Fast and lightweight JavaScript game engine built on WebGL and glTF
Open source HTML5 game framework that offers WebGL and Canvas
Open Source MMORPG Framework
A game framework written with osu! in mind.
ThinkPHP Framework
Open source library for creative expression on the web, desktop, etc.
Self-hosted CMS platform based on the Laravel PHP Framework
Gideros Release version
CTFs as you need them
You can make it - Open Source MMORPG Platform
lua dev plugin for unreal engine 4 or 5
Open source library for N64 development
utility collection for 2D game development in Java; sound-player
Arianne is an engine to develop multiplayer online games like Stendhal
An isometric arcade-style game of skill, puzzles and exploration
Game engine supporting many 3D/2D formats and graphic effects
Old-school 2D game engine
Orx: Data-Driven Game Engine
JavaScript framework to build game engines, games, emulators and apps