Yepnope.js
An Asynchronous Conditional Resource Loader
Taggd
A tool to show and add tags to images
Poly
Small, fast, awesome. The only ES5-ish set of polyfills (shims) you can mix-and-match because they're individual AMD modules.
Xdate
A Modern JavaScript Date Library
Stringformatter
JS string formatter that supports objects, currency, date/time, decimals, and more supports easy extension and garbage collection ... goes far beyond sprintf approach.
Numeral
A javascript library for formatting and manipulating numbers.
Flexie
Legacy support for the CSS3 Flexible Box Model
Angled Edges
:triangular_ruler: Quickly create angled section edges using only Sass
Console.message
Console messages for cool kids
Selectivizr
Selectivizr is a JavaScript utility that emulates CSS3 pseudo-classes and attribute selectors in Internet Explorer 6-8.
Moment
Parse, validate, manipulate, and display dates in javascript.
Store
A better way to use localStorage and sessionStorage
Sugar
A Javascript library for working with native objects.
ES5 Shims
ECMAScript 5 compatibility shims for legacy JavaScript engines
Auto Numeric
autoNumeric is a jQuery plugin that automatically formats currency (money) and numbers as you type on form inputs. It supports most International numeric formats and currency signs including those used in Europe, North and South America, Asia and India (lakhs**).
Respond
A fast & lightweight polyfill for min/max-width CSS3 Media Queries (for IE 6-8, and more)
jQuery Number
Easily format numbers for display use. Replace numbers inline in a document, or return a formatted number for other uses.