Godot is a powerful cross-platform game engine
Open Source MMORPG Framework
A simple and easy-to-use library to enjoy videogames programming
Open source HTML5 game framework that offers WebGL and Canvas
Gideros Release version
One framework for creating powerful cross-platform games
Real Time Strategy game engine supporting early Westwood classics
Desktop/Android/HTML5/iOS Java game development framework
Open source library for creative expression on the web, desktop, etc.
ThinkPHP Framework
lua dev plugin for unreal engine 4 or 5
Open source library for N64 development
A game framework written with osu! in mind.
Unity3D Client And C# Server Framework
Self-hosted CMS platform based on the Laravel PHP Framework
Old-school 2D game engine
Game engine supporting many 3D/2D formats and graphic effects
Arianne is an engine to develop multiplayer online games like Stendhal
JavaScript framework to build game engines, games, emulators and apps
INSTEAD - Simple Text Adventure Interpreter.
Orx: Portable Game Engine
Examples of procedural geometry for Unity3D C#
Molecular viewer and prototyping framework