Bulma

Bulma is an open source CSS framework based on Flexbox and built with Sass. It’s 100% responsive, fully modular, and available for free.

Angular Material

Angular Material is both a UI Component framework and a reference implementation of Google’s Material Design Specification.

Simple and flexible HTML, CSS, and JS for popular UI components and interactions

Element, a Vue 2.0 based component library for developers, designers and product managers.

The most advanced responsive front-end framework in the world

Simple. Robust. Responsive. Flexible.

A rock-solid default for HTML5 awesome.

World’s smallest responsive CSS framework (398 bytes!)

A CSS Framework and a Set of React Components that Implement Google’s Material Design

A minimalist CSS framework

Polymer is a library that uses the latest web technologies to let you create custom HTML elements.

A set of small, responsive CSS modules that you can use in every web project.

A UI Component library implemented using a set of specifications designed around natural language

Spectre is a web application to diff screenshots.

A lightweight and modular front-end framework for developing fast and powerful web interfaces

A colorful CSS framework made by a human not an AI

Material Component Framework for VueJS 2

A phone carrier that is actually nice to you.

W2UI is a small JavaScript UI library with a complete set of widgets: layout, grid, sidebar, toolbar, tabs, fields, popup, utilities.