A front-end developer toolkit
Because I think that the best css/js toolkit is composed by many agnostic micro libraries.
A Sass mixin that helps you compose media queries in an elegant way.
My favourite to make perfectly customized media queries
Touch, responsive, flickable carousels
Not perfect, but better than buggy owl carousel
A declarative pattern for applying CSS states and animations based on user interaction
For things like responsive nav
Agnostic utility for adding momentum to anything. It's like iScroll, except not for scrolling. Supports mouse and touch events.
Simple but very limited (no callbacks)
A Sass mixin for creating hamburger icons.
Untested but very promising
Medium's Image Zoom for jQuery