Stringformatter
JS string formatter that supports objects, currency, date/time, decimals, and more supports easy extension and garbage collection ... goes far beyond sprintf approach.
Hitch
A lightweight engine that allows you to hitch new capabilities to the browser (prollyfill).
Taggd
A tool to show and add tags to images
Date
Date() for humans
Sugar
A Javascript library for working with native objects.
HTML5shiv
This script is the defacto way to enable use of HTML5 sectioning elements in legacy Internet Explorer.
Moment
Parse, validate, manipulate, and display dates in javascript.
Flexie
Legacy support for the CSS3 Flexible Box Model
Yepnope.js
An Asynchronous Conditional Resource Loader
Numeral
A javascript library for formatting and manipulating numbers.
Angled Edges
:triangular_ruler: Quickly create angled section edges using only Sass
Store
A better way to use localStorage and sessionStorage
Decimal.js
An arbitrary-precision Decimal type for JavaScript
Datejs
Datejs is an open-source JavaScript Date Library.
Underscore String
String manipulation extensions for Underscore.js javascript library.
Mathjs
An extensive math library for JavaScript and Node.js
Console.message
Console messages for cool kids