Prettier : Prettier is an opinionated code formatter. It enforces a consistent style by parsing your code and re-printing it with its own rules that take the max...
* { CSS:resetr } : To help you find the perfect CSS-reset styles, CSSresetr lets you try all the best CSS Resets on a variety of web pages – even your own.
Selectivizr : CSS3 pseudo-class and attribute selectors for IE 6-8
PurgeCSS : PurgeCSS is a tool to remove unused CSS. It can be part of your development workflow.
stylelint : A mighty, modern CSS linter that helps you enforce consistent conventions and avoid errors in your stylesheets.
PostCSS plugin to parse CSS and add vendor prefixes to CSS rules using values from Can I Use.