Modernizr
Modernizr is a JavaScript library that detects HTML5 and CSS3 features in the user’s browser.
Rambda
Faster alternative to Ramda in just 10kB
Backbone.stickit
Backbone data binding, model binding plugin. The real logic-less templates.
Q
A tool for making and composing asynchronous promises in JavaScript
Webshim
Webshims Lib is a modular capability-based polyfill-loading library
Backbone Layout Manager
A layout and template manager for Backbone.js applications.
Page.js
Micro client-side router inspired by the Express router (~1200 bytes)
History.js
History.js gracefully supports the HTML5 History/State APIs (pushState, replaceState, onPopState) in all browsers. Including continued support for data, titles, replaceState. Supports jQuery, MooTools and Prototype. For HTML5 browsers this means that you can modify the URL directly, without needing to use hashes anymore. For HTML4 browsers it will revert back to using the old onhashchange functionality.
Autolink Js
Tiny little tool to find URLs in a string of text and hyperlink them
PreloadJS
PreloadJS makes preloading assets & getting aggregate progress events easier in JavaScript. It uses XHR2 when available, and falls back to tag-based loading when not.
Csso
CSS-optimizer
Sticky Kit
A jQuery plugin for creating smart sticky elements
Supermodel
Supermodel - Minimal Model Tracking for Backbonejs
Machina.js
js ex machina - finite state machines in JavaScript
Stampit
Create objects from reusable, composable behaviors.
Radio
Dependency-free Chainable Publish/Subscribe Library for Javascript
Visibility.js
Visibility.js allows you to determine whether your web page is visible to a user, is hidden in background tab or is prerendering. It allows you to use the page visibility state in JavaScript logic and improve browser performance by disabling unnecessary timers and AJAX requests, or improve user interface experience (for example, by stopping video playback or slideshow when user switches to another browser tab).