Scripting platform, modding framework and VR support for RE Engine
Unity / XNA game patcher and plugin framework
A framework to build Pokémon RPG games
Create Minecraft bots with a powerful and high level JavaScript API
A lightweight game server framework implemented with Actor Model
UI Automation Framework for Games and Apps
A lightweight online game framework
MAME is a multi-purpose emulation framework
Godot game template and component-based framework
Phaser is a free and fast 2D game framework for making HTML5 games
3D game engine/framework in C, with Luajit and Python bindings now
Cross-platform runtime for cloud, mobile, desktop, and IoT apps
A fast and reliable entity component system (ECS) and much more
Multiplayer Framework for Node.js
Open source and cross-platform machine learning framework for .NET
Telegram Bot API for Java
2D GPU-accelerated framework for ActionScript developers
A grid based movement engine compatible with Phaser3
A free (libre) open source, mobile OS for Ethereum
An asynchronous event driven PHP socket framework
Access serial ports with JavaScript. Linux, OSX and Windows
A fast entity component system (ECS) for C & C++
SDL library for Android, including several games.
Arianne is an engine to develop multiplayer online games like Stendhal
LÖVE is an awesome 2D game framework for Lua