1. Useful Links

Here you can find a list of URLs that may help you with theme using or creating. This list was originally written by bvc and improved by GnomeArt team.

1.1. Looking for help

GnomeArt Tutorials
Forum on Gnome Themes page
Gnome Support Forum, see sections GNOME Art and GNOME Art Devel

1.2. Looking for themes

Art.Gnome.org
Gnome-Look.org
Ubuntu Artwork
Themes on Freshmeat.net
DeviantArt.com

1.3. Useful docs & links

Gtk+ Reference Manual
GNOME Human Interface Guidelines
Some notes about how different widgets are drawn
GtkTheming docs by benzea
A pixmap images resource - the .wba extension is seen as a zip type by file-roller ;)
Gtk Stock Items
Standard Icon Naming Specification by Tango project

1.4. A SVG resources

librsvg project page
Inkscape vector editor - has a built in tutorial
Sodipodi vector editor
Programmer-Art.org

1.5. Themes

Gtk Engines download page on Art.Gnome.org
SmoothGNOME
Smooth Gtk Engine 0.5 docs
Smooth Gtk Engine SF page
eXperience

1.6. Useful tools

metacity-theme-viewer (URL, Screenshot)
Original metacity testing tool, you can find out how fast your theme loads and errors pointing to any problems with loading the theme. It opens a gui to show you all the different aspects of the theme.
Start it using command: metacity-theme-viewer <theme_name>

The Widget Factory (URL, Screenshot)
A Gtk theme viewing tool written by Remenic (Richard Stellingwerff). This tool allows you to see all gtk widgets in all positions and states.
Start it using command: twf

Art Stuff from Benjamin Berg (http://benjamin.sipsolutions.net/Projects/art-stuff)
A couple of scripts that may be usefull when working with GNOME Artwork.

• GDM Screenshot utility
• GTK+ theme preview and "difference" calculator
• Converter to move icon themes to the one canvas workflow
• and more ...

ArtWeb Preview (No public download, Screenshot)
This useful tool helps you to create a Gtk, MCity and icon theme preview images. Originally written by thos (Thomas Wood) but note there is no public version release yet.
Not for public use yet, you can ask on #gnome-art @ irc.gnome.org for a copy

GIB (GNOME Iconset Builder) (URL1, URL2, URL3, URL4, No Screenshot)
GIB (GNOME Iconset Builder) allows you to create icon themes for GNOME with ease. No more manual copy/resize/move/convert/rename actions. GIB automatically does this for you and organizes the icons in a GNOME compliant theme. It is suitable for rapidly generating icon themes from existing (non-theme) iconsets.

Metacity Theme Editor (URL, Screenshot)
Metacity Theme Editor is a theme editor for the Metacity window manager written by thos (Thomas Wood). It is currently in early stages of development, and still has a number of bugs.

GTK theme/engine torturer and crash tester (URL, Screenshot1, Screenshot2, Download)
This "gtk-theme-torturer" is an application to detect performance issues in GTK themes/engines.

There is a improved version from Benjamin Otte for performance tests available from git://people.freedesktop.org/~company/git/gtk-theme-torturer.

For crash testing there is a more extensive test in the test directory of gtk-engines.

Other Gnome tools
Visit GnomeFiles.org page, a Gnome application database.

2. Related links

How color-blind people see your UIs (Kirill Grouchnikov's Blog)