Babylon.js
Babylon.js: a complete JavaScript framework for building 3D games with HTML 5 and WebGL
Melon JS
a fresh & lightweight javascript game engine
Nipplejs
A virtual joystick for touch capable interfaces.
Turbulenz Engine
Turbulenz is a modular 3D and 2D game framework for making HTML5 powered games for browsers and mobile devices.
Joy.js
A Joyful 2D HTML5 Game Engine.
Rot.js
ROguelike Toolkit
Crafty
Crafty is a JavaScript game library that can help you create games in a structured way.
Kiwi.js
Kiwi.js is a blazingly fast mobile & desktop browser based HTML5 game framework. It uses CocoonJS for publishing to the AppStore.
Blend4 Web
Blend4Web is a tool for interactive 3D visualization on the Internet
Cutjs
Lightweight, fast, interactable 2D HTML5 rendering engine for cross-platform game development.
PhysicsJS
A modular, extendable, and easy-to-use physics engine for javascript
Flash JS
JavaScript graphics and games engine with API familiar to Flash one. Just look to examples sources.
Chem
html5 game engine optimized for rapid development
Phina.js
phina.js is game library
Matter JS
a 2D rigid body physics engine for the web
Superpowers Core
:octopus: Superpowers — Extensible HTML5 app for real-time collaborative projects
Canvas Engine
Framework for HTML5 Canvas oriented 2D video games