Enter the URL of any CSS file to view and modify its color spectrum
With this bookmarklet you can click a html element and get and edit an XPath/CSS Path expression to it.
Deadweight is RCov for CSS, kind of. Given a set of stylesheets and a set of URLs, it determines which selectors are actually used and reports which can be "safely" deleted.
Helium is a tool for discovering unused CSS across many pages on a web site. The tool is javascript-based and runs from the browser.