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.
UnCSS : UnCSS is a tool that removes unused CSS from your stylesheets. It works across multiple files and supports Javascript-injected CSS.
stylelint : A mighty, modern CSS linter that helps you enforce consistent conventions and avoid errors in your stylesheets.
Compass : Compass is an open-source CSS Authoring Framework.