library
Codeigniter CRUD Generator : GroceryCrud
GroceryCrud is a Codeigniter CRUD generator library that can auto-generate a fully-functional create/read/update/delete interface very quickly

Open Source Social Services Authentication Library : HybridAuth
HybridAuth is an open source authentication and authorisation solution that combines the strengths of several major social networks and ID (Identity Providers) services into one simple PHP Library.
WebKit CSS 3D Positioning Using Javascript Library : Sprite3D.js
Sprite3D is a simple javascript library that can help you to making things move in 3D space in webkit browsers using CSS transforms. you don’t need a <canvas> object (and its performance problems), nor a WebGL enabled browser.

Open Source JavaScript Date Library : Datejs
Datejs is an open source JavaScript date Library developed by Geoffrey McGill and Coolite team. It’s Comprehensive, yet simple, stealthy and fast. Datejs doesn’t just parse strings, it slices them cleanly in two.

Javascript Charting Library : Elycharts
Elycharts is a pure javascript charting library, easy to use and completely customizable. It helps you create good looking interactive charts on you web pages or web applications, with a lot of useful features

Cross-Browser JavaScript Library for Creating Interactive Diagrams : JointJS
JointJS is a JavaScript library for creating diagrams. The diagrams can be fully interactive. Joint library is suitable for both implementing a diagramming tool as well as simply for publishing your diagrams.

Free & Open Source Library for Create a Tour of Your Site : Amberjack
Amberjack is an Open Source library you can use to create tours that guide your site’s visitors. The basic idea is to explain existing pages of your site through a text (like this).

A Library for Making Select Boxes More User-Friendly : Chosen
Chosen is a javascript plugin makes long, unwieldy select boxes much more user-friendly. It is currently available in both jQuery and Prototype flavors.

Complete jQuery UI Library & Framework : EasyUI
EasyUI is a complete UI Library and framework for creating simple or advanced interfaces to build your web page easily.

PDF Document Generation Library for Node : PDFKit
PDFKit is a PDF document generation library for Node that makes creating complex, multi-page, printable documents easy. It is written in pure CoffeeScript, but you can choose to use the API in plain ‘ol JavaScript if you like.