yepnope.js : A Conditional Loader For Your Polyfills!
SlimerJS : A scriptable browser for Web developers
boomerang : boomerang is a piece of javascript that you add to your web pages, where it measures the performance of your website from your end user's point of vie...
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.