Phina.js
phina.js is game library
Joy.js
A Joyful 2D HTML5 Game Engine.
Frozen
Frozen is an open-source HTML5 game engine delivering ease-of-use, rapid development through tooling and modularity.
Chem
html5 game engine optimized for rapid development
Matter JS
a 2D rigid body physics engine for the web
Enchant.js
A simple JavaScript framework for creating games and apps
PhysicsJS
A modular, extendable, and easy-to-use physics engine for javascript
Easystar.js
An asynchronous A* pathfinding API written in Javascript.
Flash JS
JavaScript graphics and games engine with API familiar to Flash one. Just look to examples sources.
Panda.js
Panda.js HTML5 game engine
Lychee JS
Environment-Independent JavaScript engine (HTML5 Canvas, V8GL, WebGL, native OpenGL, NodeJS)
Playground
Playground.js is a framework for your javascript based games. It gives you out-of-box access to essentials like mouse, keyboard, sound and well designed architecture that you can expand to your needs.
Limejs
HTML5 game framework for web and iOS
Canvas Engine
Framework for HTML5 Canvas oriented 2D video games
Verlet JS
A simple Verlet physics engine written in javascript
Crafty
Crafty is a JavaScript game library that can help you create games in a structured way.
Egret Core
Egret is a brand new open mobile game and application engine which allows you to quickly build mobile games and apps on Android,iOS and Windows.