JS string formatter that supports objects, currency, date/time, decimals, and more supports easy extension and garbage collection ... goes far beyond sprintf approach.
Typecast.js :: Solving the simple problems
Small, fast, awesome. The only ES5-ish set of polyfills (shims) you can mix-and-match because they're individual AMD modules.
Console messages for cool kids
Tiny polyfill for the placeholder form element attribute. Requires Prototype.js.
CSS4 parent selector based on jQuery
A simple helper to extract values from a string based on a pattern.