Workbox : JavaScript Libraries for adding offline support to web apps.
rsvp.js : A lightweight library that provides tools for organizing asynchronous code
Dropzone.js : DropzoneJS is an open source library that provides drag'n'drop file uploads with image previews.
Protovis : Protovis composes custom views of data with simple marks such as bars and dots. Unlike low-level graphics libraries that quickly become tedious for vi...
RequireJS : RequireJS is a JavaScript file and module loader. It is optimized for in-browser use, but it can be used in other JavaScript environments, like Rhino ...
A simple library for handling keyboard shortcuts in Javascript.