1. Bootstrap

Bootstrap is definitely the most popular and widely used framework, nowadays. It’s a beautiful, intuitive and powerful web design kit for creating cross browser, consistent and good looking interfaces. It offers many of the popular UI components with a plain-yet-elegant style, a grid system and JavaScript plugins for common scenarios.

It is built with LESS and consists of four main parts:

• Scaffolding – global styles, responsive 12-column grids and layouts. Bear in mind that Bootstrap doesn’t include responsive features by default. If your design needs to be responsive you have to enable this functionality manually.
• Base CSS – this includes fundamental HTML elements like tables, forms, buttons, and images, styled and enhanced with extensible classes.
• Components – collection of reusable components like dropdowns, button groups, navigation controls (tabs, pills, lists, breadcrumbs, pagination), thumbnails, progress bars, media objects, and more.
• JavaScript – jQuery plugins which bring the above components to life, plus transitions, modals, tool tips, popovers, scrollspy (for automatically updating nav targets based on scroll position), carousel, typeahead (a fast and fully-featured autocomplete library), affix navigation, and more.

Bootstrap is already powerful enough to empower any web interface. But in order to make more use of it and making the development process easier, you can find plenty of tools and resources that complement it. Some of them are listed below:

• jQuery UI Bootstrap – an awesome resource for jQuery and Bootstrap fans that combines the power of both. It brings nicely the slickness of Bootstrap to jQuery UI widgets.
• jQuery Mobile Bootstrap Theme – similar to the jQuery UI theme above, this is a theme built for jQuery Mobile. It is a handy resource if you have a web front-end built with Bootstrap and want to offer a similar look for mobile.
• Fuel UX – this extends Bootstrap with additional lightweight JavaScript controls. It’s easy to install, customize, update, and optimize.
• StyleBootstrap.info – Bootstrap has its own customizer but StyleBootstrap is a more detailed one with color pickers and the ability to style each component differently
• BootSwatchr – a Bootstrap theme roller that shows the immediate results of your changes. For every generated style, the application generates a unique URL in case you want to share it with others or return and edit anytime later.
• Bootswatch – a nice set of free themes for Bootstrap.
• Bootsnipp – a good collection of design elements and HTML snippets for Bootstrap. It offers also form and button builders.
• LayoutIt – drag and drop interface builder based on the elements and components of Bootstrap. It helps you to compose your design visually by placing and arranging different elements into your layout via drag and drop and then allows you to edit their properties. You get the base code and then expand it. Simple and easy.

2. Fbootstrapp

Fbootstrapp is based on Bootstrap and gives you the same functionality for Facebook iframe apps and designs. It includes base CSS and HTML for all standard components like typography, forms, buttons, tables, grids, navigation, and more, styled in the typical Facebook look and feel.

3. BootMetro

BootMetro is a framework inspired by the Metro UI CSS, which is built on top of Bootstrap, for creating Metro/Windows 8-styled websites. It includes all Bootstrap’s features plus some additional extras like tiled pages, an application bar, and more.

4. Kickstrap

Simply put, Kickstrap is a kind of Bootstrap on steroids. It uses Bootstrap as its base and extends it with many apps, themes and extras. This makes the framework a complete kit for building websites without the need to install anything. Just put it in your site and you are ready to go.

Apps are just bundles of JavaScript and CSS files that run together as a package after your page has finished loading. Some of the apps included by default are Knockout.js, Retina.js, Firebug Lite, and Updater. And you can add many more.

Themes give you the ability to differentiate from most Bootstrap websites’ standard look and feel.

Extras are fan-created additions to extend Bootstrap UI library. They usually use the same or similar syntax.

5. Foundation

Foundation is a powerful, feature-rich, responsive front-end framework. With Foundation you can quickly prototype and build websites or apps that work on any kind of device, with tons of included layout constructs, elements and best practices. It’s built with mobile first in mind, utilitizes semantic features, and uses Zepto instead of jQuery in order to brings better user experience and faster performance.

Foundation has a 12-column flexible, nestable grid powerful enough to let you create rapidly multi-device layouts. In terms of features it provides many. There are styles for typography, buttons, forms, and various navigation controls. Many useful CSS components are provided like panels, pricing tables, progress bars, tables, thumbnails, and flex video that can scale properly your video on any device. And, of course, JavaScript plugins including dropdowns, joyride (a simple and easy website tour), magellan ( a sticky navigation that indicates where you are on the page), orbit (a responsive image slider with touch support), reveal (for creating modal dialogs or pop-up windows),  sections (a powerful replacement for traditional accordions and tabs), and tooltips.

The framework also offers many useful add-ons.

• Stencils – all UI elements available in Foundation in a form of Omnigraffle stencils and vector PDFs for building wireframes and mock-ups faster and more easily.
• HTML Templates – handy, ready to go layouts for you to quickly start from and build on. To use them you simply grab the code and drop it between the <body> tags of your page.
• Icon Fonts – these are custom icon sets of pictographic icons stored in a handy web font.
• SVG Social Icons – a set of resolution-independent social icons.
• Responsive Tables –  the mechanism of Foundation’s responsive tables is to take the first column and “pin” it to the left of the table, thus allowing you to scroll the other columns under it.
• Off-Canvas Layouts – these layouts allows you to keep content or navigation on mobile devices hidden until either a larger screen size allows it to be visible or a user takes action to expose it. And when the last happens the content or navigation slides into view.

As you can see, Foundation is like a treasure-house for web developers/designers. And in order to get only what you need you can use the customizer to build your custom download.

6. GroundworkCSS

GroundworkCSS is a new, fresh addition to the front-end frameworks family. It’s a fully responsive HTML5, CSS and JavaScript toolkit built with the power of Sass and Compass which gives you the ability to rapidly prototype and build websites and apps that work on virtually any device.

It offers an extremely flexible, nestable, fraction-based, fluid grid system that makes creating any layout possible. GroundworkCSS has some really expressive features like tablets and mobile grids which maintain the grid column structure instead of collapsing the grid columns into individual rows when the viewport is below 768 or 480 pixels wide. Another cool feature is a jQuery ResponsiveText plugin which allows you to have dynamically sized text that adapts to the width of the viewport: extremely useful for scalable headlines and building responsive tables.

The framework includes a rich set of UI components like tabs, responsive data tables, buttons, forms, responsive navigation controls, tiles (a beautiful alternative to radio buttons and other boring standard form elements), tooltips, modals, Cycle2 (a powerful, responsive content slider), and many more useful elements and helpers. It also offers a nice set of vector social icons and a full suite of pictographic icons included in FontAwesome.

To see the framework in action you can use the resizer at the top center of the browser window. This way you can test the responsiveness of the components against different sizes and viewports while exploring the framework’s features.

GroundworkCSS is very well documented with many examples, and to get you started quickly the framework also provides you with several responsive templates. The only thing I consider as a weakness is the missing of a way to customize your download.

7. Gumby

Gumby is simple, flexible, and robust front-end framework built with Sass and Compass.

Its fluid-fixed layout self-optimizes the content for desktop and mobile resolutions. It support multiple types of grids, including nested ones, with different column variations . Gumby has two PSD templates that get you started designing on 12 and 16 column grid systems.

The framework offers feature-rich UI Kit which includes buttons, forms, mobile navigation, tabs, skip links, toggles and switches, drawers, responsive images, retina images, and more. Following the latest design trends the UI elements have Metro style flat design but you can use Pretty style with gradient design too, or to mix up both styles as you wish. An awesome set of responsive, resolution independent Entypo icons, for you to use in your web projects, is completely integrated into the Gumby Framework.

Gumby has also a very good customizer with color pickers which helps you to build your custom download with ease.

8. HTML KickStart

HTML KickStart is a HTML5, CSS and jQuery-powered toolkit for easily creating any type of layout. It provides clean, standards-compliant and cross-browser mark-up.

The framework has styles for grids, typography, forms, buttons, tables or lists and cross-browser web elements like a JavaScript slideshow, tabs, breadcrumb navigation, menus with sub-menus, tooltips, and more.

You can use 99Lime UIKIT which has all the UI elements of HTML KickStart ready to be used in your wireframes.

9. IVORY

IVORY is a lightweight, simple and powerful framework that can handle responsive layouts from 320px to 1200px widths. It is packed with 12-column fluid width grid, styles for typography and some essential UI components like buttons, toggle-switches, accordions, tabs, tooltips, and more.

IVORY is a perfect choice when you need a simple and flexible, multi device solution, and your design doesn’t requires extra functionality which other frameworks offer.

10. Kube

Lastly, if you need a solid, yet simple base without needless complexity and extras, for your new project, Kube can be the right choice. Kube is a minimal, responsive and adaptive framework with no imposed styling which gives you the freedom to create. It offers basic styles for grids, forms, typography, tables, buttons, navigation, and other stuff like links or images.

The framework contains one compact CSS file for building responsive layouts with ease and two JS files for implementing tabs and buttons in your designs. If you are looking for maximum flexibility and customization, you can download developer version which includes LESS files, with variables, mixins and modules.

Conclusion

I hope that now, after reading this article, you have a better perspective on the different choices available to you for your next projects. I’ve tried to put here the most popular, feature-rich, well-structured and promising frameworks which I know at the time of this writing. But as you already know things get changed with the speed of the light. So, if you know of some other cool framework not listed here, please share your knowledge in the comments thus making this article even more useful.