Autoprefixer : PostCSS plugin to parse CSS and add vendor prefixes to CSS rules using values from Can I Use.
CSS Sprite Generator : This tool allows you to automate the process of generating CSS sprites. Simply give it a ZIP file containing 2 or more images (GIF, PNG or JPG) and it...
csscss : csscss will parse any CSS files you give it and let you know which rulesets have duplicated declarations.
Compass : Compass is an open-source CSS Authoring Framework.
UnCSS is a tool that removes unused CSS from your stylesheets. It works across multiple files and supports Javascript-injected CSS.