Foundation - The most advanced responsive front-end framework in the world
Bootstrap - Simple and flexible HTML, CSS, and JS for popular UI components and interactions
Purecss - A set of small, responsive CSS modules that you can use in every web project.
Materialize CSS - A modern responsive front-end framework based on Material Design
Refills - Refills are prepackaged patterns and components, built on top of Bourbon, Bitters and Neat.
Semantic UI - A UI Component library implemented using a set of specifications designed around natural language