Headroom.js : Headroom.js is a lightweight, high-performance JS widget (with no dependencies!) that allows you to react to the user's scroll.
Vex : Vex is a modern dialog library which is highly configurable, easily stylable, and gets out of the way. You'll love vex because it's tiny (6kb minified...
Frappe Charts : GitHub-inspired simple and modern charts for the web with zero dependencies.
loglevel : Minimal lightweight logging for JavaScript, adding reliable log level methods to wrap any available console.log methods
yepnope.js : A Conditional Loader For Your Polyfills!