Here are List of best Free WordPress Themes or Templates on net, some of them are premium quality free wordpress themes.
15 Free Premium-like WordPress Themes from Noupe
Awesome 100 free high-quality WordPress themes from Smashing Magazine,
83 free WordPress Themes you probably haven’t seen yet. All themes offer quality, elegance and a user-friendly interface from Smashing Magazine,
In this article they present over 30 fresh free high-quality WordPress themes. All themes can be downloaded, customized and used for free — in personal or/and commercial projects.
Official WordPress Free Theme Directory
Great Collection of Free WordPress Themes and Plugins
Another Greate Collection of Free WordPress themes
Nice Collection of Free WordPress themes