yepnope.js : A Conditional Loader For Your Polyfills!
PhantomJS : PhantomJS is a headless WebKit with JavaScript API. It has fast and native support for various web standards: DOM handling, CSS selector, JSON, Canvas...
Zombie.js : Zombie.js is a lightweight framework for testing client-side JavaScript code in a simulated environment. No browser required.
jscs is a code style checker. jscs can check cases, which are not implemented in jshint, but it does not duplicate jshint functionality, so you should use jscs and jshint together.