Wave.js : Audio visualizer library for javascript. Create dynamic animations that react to an audio file or audio stream.
Headroom.js : Headroom.js is a lightweight, high-performance JS widget (with no dependencies!) that allows you to react to the user's scroll.
InstantClick : InstantClick is a JavaScript library that dramatically speeds up your website, making navigation effectively instant in most cases.
polyfill : polyfill makes web development less frustrating by selectively polyfilling just what the browser needs. Use it on your own site, or as a service.
Bespoke.js : Bespoke.js is a super minimal, modular presentation library for modern browsers, designed to foster a rich plugin ecosystem.
Namespace.js is a small javascript script which provide namespacing utilities. It is framework independent. It also allows you to remotely include files.