The Bluebird theme

The GTK+ theme is based on Zuki Blues by Lars Kongo (lassekongo83), and the xfwm theme is based on axiom by Rogier Koppejan (roog).

Bluebird also has Metacity support.

Greybird, the Bluebird successor

We created a new less-saturated version of Bluebird, called Greybird. Read more about it from the Greybird project page.