The folks at WordPress Themes Archive have have collected over 2ooo WordPress themes and are offering the themes as a single archive for the benefit of the users. Currently at around 390 mb, users are given the option of downloading the entire collection of WordPress themes as .ZIP, .TAR.GZ or .TORRENT.
The collection contains themes classified in terms of columns too – single, two column, three column and four column WordPress themes which are available for download as separate files. An additional link is added to the footer as a small price to feature in the WordPress Theme Archive. However, if you’d like to remove your theme from the list, you may contact them and they’ll remove it immediately. You can add your theme to the archive list in the same way.
You can download them here: http://wptmp.com/