CSS Ratiocinator - A tool that will automatically refactor your CSS
Optimse your CSS. A new take at an old issue.
gradient-scanner
Handy too to pick up a gradient from an image
Prefixr
Generate cross-browser CSS
spin.js
Generate a cross-browser spinner in CSS
30 Must Have Free Mac Apps for Web Designers and Developers
8 Fast and Furious Tools to speed up your CSS and HTML Coding Time
Patternify | CSS Pattern Generator
gridr buildrrr
Grid builder
CSS3 Please! The Cross-Browser CSS3 Rule Generator
You can edit the underlined values in this css file but don't worry about making sure the corresponding values match, that's all done automagically for you.
LESS - Leaner CSS
LESS extends CSS with variables, mixins, operations and nested rules
zen-coding
Set of plugins for HTML and CSS hi-speed coding