WordPress themes suitable for designers are listed below. There are obviously more. Many offer free along with paid themes. Take a look at these, browse through all since they’re not listed in any order. Get a sense of the kind of format you’d like.
WordPress Commercial Themes – come with support
Pagelines theme – featuring drag and drop
Theme Trust – elegant design
Check out the free themes on WordPress.org
themify tumblr-like themes
wp shower
dessign.net
Elefolio
WPBundle (a bundle of themes)
WPImpact
Theme Trust
Feather Weight/Allan Cole