lighter.css is a lightweight, responsive, mobile-compatible CSS/CSS3 framework for modern, cross-platform front-end development.
teutonic.css is a versatile, pure CSS/CSS3 Framework to help web developers to build responsive, accessible, modern webpage/webapp.
Yet another small CSS framework that helps developers and beginners to quickly create fully responsive, nested grid layouts using CSS flexbox model.
lemon is a simple, lightweight, pure CSS front-end framework that helps you create responsive, clean websites and web applications.
A responsive, customizable, modular and open source HTML5/CSS/SCSS framework for creating modern clean web pages and web applications.
lit.css is a minimal (less than 1kb minified) CSS framework to help you create responsive, pretty clean web app.
chota.css is a super light, pure CSS framework to help you create responsive, minimal, clean web pages and/or modern web apps.