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.
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...
PurgeCSS : PurgeCSS is a tool to remove unused CSS. It can be part of your development workflow.
YAML Builder : A tool for visual layout development of YAML based CSS layouts
UnCSS is a tool that removes unused CSS from your stylesheets. It works across multiple files and supports Javascript-injected CSS.