I like to give an analogy of a car (cars = themes, bear with me). When building a new car, everything isn’t reinvented. Your not going to find innovation in tires or in a steering wheel from the new Dodge Grand Caravan. Instead, you’d probably find innovation through the features it sports. What results, is a lot of cars using the same parts. So can WordPress themes. It’s all about being more efficient in your craft. Factor out all the essential theme parts and use them as the bases for the framework. In doing this, you’ll dramatically speed up the time it takes to build recurring themes from scratch.
Theme Hybrid themes are created with a lot of special care. Hours upon hours of testing, debugging, and planning are put into each theme. Feel free to browse around and choose one to use for free.
“We’ve added a development changelog page to the site here so you can see recent changes to the Carrington framework and themes. This is part of a larger effort to create more developer resources, including some tutorials and overviews of the framework.”
WP Framework is another free WordPress Theme Framework. Its aim is to serve as a starting point for a new WordPress theme and one that can be easily modified. It is very well documented for easy customization, is amazingly flexible, extensible and modular, and is always sure to work with the latest WordPress versions. WP Framework also has got an auto-upgrading feature which makes sure you’ve always got the latest version of the theme on your server.
Whiteboard is a theme framework coded for simplicity. It is very light (76KB, unzipped), and includes all the files needed for a complete WordPress theme development. Whiteboard comes with with a template for archive page, categories page, pagination post and socialization links. Whiteboard is completely compatible with WordPress version 2.7.
Ashford is a WordPress Theme Framework built to be a simple to use and equally as simple to modify. Ashford is a two column, widget-ready, gravatar enabled theme which enables easy customization through child themes. Of course, Ashford is search engine optimized, freeing you from the task of doing SEO.
OnePress is another WordPress Theme Framework which is available for free. It is meant to be used as a website and forum combo. It integrates seamlessly with phpBB, coupled with unified login and forum posts display on the website. It is widget-ready, with highly optimized page rendering for improved performance. OnePress works on WordPress 2.7 and up, and allows easy creation of child themes.
Sandbox is a minimalist WordPress Theme Framework which allows developers to build new themes upon. New themes can be developed by just using CSS. Sandbox is meant to be used on WordPress version 2.6+. It is fully widget-ready, XHTML valid and released under GNU GPL.
Starkers is a blank WordPress theme for you to use to create a new design upon. It is completely semantic, cleanly coded blank template. The CSS has also been reset so that no problems are caused across different browsers.
Vanilla is a WordPress theme framework which is designed to be really powerful and easy to customize without needing any knowledge of PHP. It is built upon PHPTAL templating engine, has pre-loaded template styles for different website uses, uses Carrington (reviewed above) atomic templating system, loads of widgetized areas, support for child themes and more.
WP Constructor is another very good WordPress theme framework. It features 6 different sidebar options, very clean code and a very advanced theme options page which enables you to modify nearly every aspect of the theme from the WordPress dashboard.
Brave New World is a blank WordPress theme for you to work upon to make your next WordPress theme. It incorporate lastest technologies like HTML5, ARIA and more.
Thesis is a commercial WordPress theme framework which is insanely flexible. Thesis is search engine optimized, designed with accessibility and usability in mind.
WordPreciousss is another basic WordPress Theme, which you can create child themes for. It is very basic in design, featuring one one widgetized sidebar, has been tested in nearly every major browser.
WordPress Naked was design to be a simple, easy to customize WordPress theme for new projects. It is lightweight, and XHTML valid, has a 2 column CSS layout, and is search engine optimized.