Typeit
The most versatile JavaScript typewriter effect library on the planet.
Dojo
Dojo saves you time and scales with your development process, using web standards as its platform. It’s the toolkit experienced developers turn to for building high quality desktop and mobile web applications.
Featherlight
Featherlight is a very lightweight jQuery lightbox plugin. It's simple yet flexible and easy to use. Featherlight has minimal css and uses no inline styles, everything is name-spaced, it's completely customizable via config object and offers image, ajax and iframe support out of the box. Featherlights small footprint weights about 4kB – in total.
Grid
Drag and drop library for two-dimensional, resizable and responsive lists
Proton
A particle engine for html5
Remote Storage
Client-side Javascript library to make apps compatible with a remote storage.
Smoothie
Smoothie Charts: smooooooth JavaScript charts for realtime streaming data
Rainbow
Simple syntax highlighting library written in javascript
Shuffle
jQuery Shuffle Plugin
Swipebox
A touchable jQuery lightbox
Twig.js
JS implementation of the Twig Templating Language
Responsive Slides
Simple & lightweight responsive slider plugin (in 1kb)
JS Plumb
jQuery/MooTools/YUI3 Javascript library that lets you connect parts of your UI together.
Keypress
A keyboard input capturing utility in which any key can be a modifier key.
Oimo.js
Lightweight 3d physics engine for javascript
Jquery Tokeninput
Tokeninput is a jQuery plugin which allows your users to select multiple items from a predefined list, using autocompletion as they type to find each item. You may have seen a similar type of text entry when filling in the recipients field sending messages on facebook.
P2.js
JavaScript 2D physics library