I decided to put some scripts I wrote into a git repository. Right now it does not contain a lot, but maybe it'll grow.
The repository is at:
git clone https://git.sipsolutions.net/art-stuff.git
You can also browse it online https://git.sipsolutions.net/art-stuff.git.
In gdm there is a bash script to create a screenshot of a GDM theme using a virtual X server (Xvfb). It can screenshot GDM themes at any size and depth.
There is also a creategdmscreenshots script, that I am now again using to create automated screenshots of GDM themes submitted to art.gnome.org. (http://benjamin.sipsolutions.net/ago/gdm). I hope it'll work now, as I had a setup like this quite a while ago, but it would fail to screenshot themes way too often.
In doc/style-properties is the script I used to create http://live.gnome.org/GnomeArt/Tutorials/GtkThemes/StyleProperties.
Scripts to create screenshots of different engine versions. The result is at http://benjamin.sipsolutions.net/screenshots/gtk-engines.
A script to aggregate icons into one canvas, so that one can convert icon themes to the one canvas workflow more easily.
I am not updating this site regularily. So see the git repository for the available scripts.