Rickshaw : Rickshaw is a JavaScript toolkit for creating interactive time series graphs.
Prototype : Easy Ajax and DOM manipulation for dynamic web applications
impress.js : It's a presentation framework based on the power of CSS3 transforms and transitions in modern browsers and inspired by the idea behind prezi.com
DOMAssistant : The modular lightweight JavaScript library, with CSS selectors, event handling, AJAX and complete Unicode support
React : A JavaScript library for building user interfaces
A library to generate PDFs in client-side JavaScript.