Selectivizr
Selectivizr is a JavaScript utility that emulates CSS3 pseudo-classes and attribute selectors in Internet Explorer 6-8.
Nerdamer
a symbolic math expression evaluator for javascript
Css3 Finalize
Tired of adding prefix for each broswer when it comes to the new css3 attributes?
Char Funk
a Unicode character utility for JavaScript
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**).
Args.js
Create javascript functions with optional, default, grouped and named parameters.
Poly
Small, fast, awesome. The only ES5-ish set of polyfills (shims) you can mix-and-match because they're individual AMD modules.
Typecast.js
Typecast.js :: Solving the simple problems
Object.observe
Object.observe polyfill/shim trying to be compliant
Es6 Shim
ECMAScript 6 (Harmony) compatibility shims for legacy JavaScript engines
Ratio.js
Rational numbers for Javascript
Placeholders.js
A JavaScript polyfill for the HTML5 placeholder attribute
Core Lib
A port of the Ruby 1.9.3 corelib to coffeescript/javascript/node that conforms to rubyspec.org.
Big.js
A small, fast JavaScript library for arbitrary-precision decimal arithmetic.
Length.js
📏 JavaScript library for length units conversion.
Datejs
Datejs is an open-source JavaScript Date Library.
Taggd
A tool to show and add tags to images