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.

sass-pire

Just a more mixins and functions with SCSS for more productive projects.

vitals-scss

A minimalistic bundle of a few CSS/Sass tools for building modern, flexible websites: an improved normalize, shorthand stuff for flexbox and grid, and a fluid sizing function.