Sproutcore
JavaScript Application Framework - JS library only
Durandal
A cross-device, cross-platform client framework written in JavaScript and designed to make building Single Page Applications (SPAs) easy to create and maintain.
Aura
A scalable, event-driven JavaScript architecture for developing widget-based applications. Works with Backbone.js and other frameworks.
Ink
An HTML5/CSS3 framework used at SAPO for fast and efficient website design and prototyping
Jsblocks
Better MV-ish Framework
Nuclear Js
Reactive Flux built with ImmutableJS data structures. Framework agnostic.
Cerebral
A state controller with its own debugger
Montage
Core framework: Montage simplifies the development of rich HTML5 applications by providing modular components, real-time two-way data binding, CommonJS dependency management, and many more conveniences. Join us on irc.freenode.net#montage or https://groups.google.com/d/forum/montagejs
Postal.js
JavaScript pub/sub library supporting some advanced subscription features, plus message capture and replay
Pencilblue
Full stack online publishing and CMS for Node.js
Remote Storage
Client-side Javascript library to make apps compatible with a remote storage.
Batman
Fighting Crime and Kicking Apps
Bootstrap.native
If you are looking for Bootstrap without jQuery or vanilla Javascript for Bootstrap, this is the place to get started.
Qooxdoo
A Universal JavaScript Framework
Simplecart
A simple javascript shopping cart that easily integrates with your current website.
Regular
a living template engine that helping us to create data-driven component.
Skel
A lightweight responsive framework for the www