Vis
Dynamic, browser-based visualization library
Rivets
Declarative data binding facility
Platform.js
A platform detection library that works on nearly all JavaScript platforms.
Flux
Application Architecture for Building User Interfaces
Qooxdoo
A Universal JavaScript Framework
Csso
CSS-optimizer
Supermodel
Supermodel - Minimal Model Tracking for Backbonejs
Javascript State Machine
A finite state machine javascript micro framework
Mediator.js
An implementation of the mediator pattern for asynchronous events in Javascript
Rx Js
The Reactive Extensions for JavaScript
Winjs
WinJS project by Microsoft Open Technologies
Uranium
Universal css-in-js media queries for React Native and React
Chaplin
An Application Architecture Using Backbone.js
jQuery Pjax
pushState + ajax = pjax
Superagent
Ajax with less suck - (and node.js HTTP client to match)
Stampit
Create objects from reusable, composable behaviors.
Aura
A scalable, event-driven JavaScript architecture for developing widget-based applications. Works with Backbone.js and other frameworks.