Updated: Nice Web Ui Frameworks

1. Foundation

Foundation is the most advanced responsive front-end framework in the world. With Foundation you can quickly prototype and build sites or apps that work on any kind of device, with tons of included layout constructs (like a full responsive grid), elements and best practices. Official site GitHub Repository

2. Metro UI

Metro UI CSS allows to create a Web site in the style of Windows 8 quickly and without distractions on routine tasks. Official site GitHub Repository

3. Groundwork

Say hello to responsive design made easy. Groundwork is a fully responsive HTML5, CSS and Javascript toolkit. Using Groundwork, you can quickly build web apps that work on virtually any device. Official site GitHub Repository

4. Goldilocks

Goldilocks is built by the team at Design by Front. The Goldilocks Approach uses a combination of Ems, Max-Width, Media Queries and Pattern Translations to consider just three states that allow your designs to be resolution independent. It contains

• 2 well commented CSS files that consider 3 CSS Media Query increments; multi column, narrow column and single column.
• Good typographic defaults out of the box (including print contexts).

View the demo here.

5. YAML

YAML, Yet Another Multicolumn Layout, is a modular CSS framework for truly flexible, accessible and responsive websites. Visit site here.

6. Gridlock

Gridlock is a responsive CSS grid system. A simple responsive grid system that will kickstart your next site build.
Percentage based responsive grid systems have issues with smaller columns on smaller screens, requiring developers to manually override column widths at specific breakpoints. Gridlock is here to fix that. By utilizing screen size specific class names and column counts, Gridlock gives designers and developers the foundation for crafting an experience that better matches the target device. Official site GitHub Repository

7. Parallax Scrolling

A responsive framework by Jalxob. Parallax Scrolling, a BETA version of Cool Kitten, is a lightweight HTML/CSS/JS toolkit for creating responsive paralax scrolling website. It makes use of Normalize.css, Stellar.js and the JQuery Easing Plugin. Official site GitHub Respository

8. Gumby 2

Introducing to you Gumby 2, a newer version and now more flexible than ever. It is a free, open-source responsive front-end development framework built with SASS. Includes Google Webfonts, Entype icons, modular scale typography and a fully customizable UI kit all built into it's extensible codebase. Official site GitHub Repository

9. Pure

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

10. iUI

A web framework for smartphones and high-end devices too! Official site Demo

11. materializecss

A modern responsive front-end framework based on Material Design. Official site