Small, fast, awesome. The only ES5-ish set of polyfills (shims) you can mix-and-match because they're individual AMD modules.
Object.observe polyfill/shim trying to be compliant
A simple helper to extract values from a string based on a pattern.
A lightweight engine that allows you to hitch new capabilities to the browser (prollyfill).
Tired of adding prefix for each broswer when it comes to the new css3 attributes?
CSS4 parent selector based on jQuery
Typecast.js :: Solving the simple problems
Tiny polyfill for the placeholder form element attribute. Requires Prototype.js.