The Bisigi Project provides 13 free, well-rounded themes you can install all at once, customized for your monitor size. Each of the 13 themes Bisigi provides has a chosen icon set, a suggested wallpaper, and color tweaks that you'll see throughout your system. Reproducible: Always
It looks like this project died during the transition from gtk2 to gtk3. There were rumors that someone was porting them to gtk3, but nothing ever materialized as far as I can tell. Since there's no upstream any more, I'm going to mark this obsolete.
