fuelux : Extends Twitter Bootstrap with additional lightweight JavaScript controls. Easy to install, customize, update, and optimize. All functionality covered...
Online javascript beautifier : Beautify, unpack or deobfuscate JavaScript and HTML, make JSON/JSONP readable, etc.
Lerna : A tool for managing JavaScript projects with multiple packages.
Babel : Babel will turn your ES6+ code into ES5 friendly code, so you can start using it right now without waiting for browser support.
