jquip : Smaller, Lighter, Faster, more modular jQuery - include only the parts you want! Don't use it, Don't include it.
SoundManager 2 : Using HTML5 and Flash, SoundManager 2 provides reliable cross-platform audio under a single JavaScript API.
Bliss.js : Want to use Vanilla JS but find native APIs a bit unwieldy? Bliss is for you
Polly.JS : Polly.JS is a standalone, framework-agnostic JavaScript library that enables recording, replaying, and stubbing HTTP interactions.
Polly taps into nat...
loglevel : Minimal lightweight logging for JavaScript, adding reliable log level methods to wrap any available console.log methods
Sammy is a tiny javascript framework built on top of jQuery, It's RESTful Evented Javascript.