Jscritic
Quickly check how well 3rd party script behaves.
Intense Images
A simple library to view large images up close using simple mouse interaction, and the full screen.
Hasher
Browser history manager for rich media websites
Domready
let's you know when the dom is ready
Canjs
Can do JS, better, faster, easier.
Apitizer
API mocking for client JavaScript applications
Animo.js
A powerful little tool for managing CSS animations
Kimbo.js
An ECMAScript 5 only-compatible JavaScript library.
Cram
Simple AMD and CommonJS module bundler.
Viewport
Gets the dimensions of the Viewport and beyond.
Jhere
jHERE - Maps made easy
Veinjs
Injects CSS into the document (it's a perfectly legal procedure)
Path.js
Simple, lightweight routing for web browsers
P5.js
A JS client-side library for creating graphic and interactive experiences, based on the core principles of Processing. http://twitter.com/p5xjs —
No Ui Slider
noUiSlider is a lightweight JavaScript range slider library. It offers a wide selection of options and settings, and is compatible with a ton of (touch) devices, including those running iOS, Android, Windows 8 and Windows Phone 8.
Zxcvbn
zxcvbn, named after a crappy password, is a JavaScript password strength estimation library. Use it to implement a custom strength bar on a signup form near you!
Lodash
An alternative to Underscore.js, delivering consistency, customization, performance, and extra features.