Elegant Themes - Simple, yet beautiful WordPress themes with easy to use implementation and support.
GPLDL - 1066 GPL-licensed WordPress themes & plugins for free
ThemeFuse - ThemeFuse is a store that provides high-quality designed WordPress themes to let you stand apart from the crowd.
Blocksy - A lightningfast, innovative and supercharged WordPress theme
ThemeGrill - ThemeGrill is an online marketplace that develops and sells WordPress themes and plugins that you can buy to create professional websites for businesses, magazines, and blogs.
LyrWP - WordPress themes / plugins / services curated.