gerillass
Gerillass is an open-source toolkit that contains a set of Sass mixins to help designers and developers to create better, faster and consistent user interfaces.
postcss-insert
A postcss plugin that inserts one css classes properties into another, like Sass @extend...only better
sass-mixkit
A lightweight collection of useful Sass mixins and functions.
sass-magics
Sass magic helper. It extends the Sass built-in modules and provides useful mixins and functions that make your Sass writing more magical and elegant.