RECESS : Developed at Twitter to support our internal styleguide, RECESS is a simple, attractive code quality tool for CSS built on top of LESS.
Incorporate it...
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...
yepnope.js : A Conditional Loader For Your Polyfills!
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.