IDesk provides icons on an X11 desktop. Its features include transparency, configurable actions to run shell commands, PNG, SVG (in old versions), GIF image support, and XFT anti-aliased fonts. Other features include Imlib2 support (Imlib is deprecated), pseudo-transparency, the ability to only show captions on mouseover, tooltip on mouseover, startup notification, and more.
Net-Fu is a DHTML implementation of the classic GIMP NET-FU interface. It uses the GNU Image Manipulation Program and Xvfb to produce a wide variety of royalty-free custom and semi-custom graphics, logos, and clip art of various sorts. You simply select a style of logo from such choices as "neon", "chrome", and "crystal", specify parameters such as text string, typeface, size, and colors, and your logo is returned without further ado.
bibivu smilies is a class that can be used to manage different packages of emoticon images. It currently supports the emoticon packages of phpBB, Yahoo! messenger, and Gaim. It can look into a given folder where the emoticon image files are stored and retrieve information about the available images, such as the picture file name and description. It may also find and replace the description text of the emoticons.
Toolbar Icons is a collection of free toolbar icons. All icons are available as (Inkscape) SVG files. OMake build scripts that automatically generate PNG files of basically any size (using Inkscape) are included. PNG files in a few default sizes (16 x 16, 24 x 24, 32 x 32, and 256 x 256) are prepared in .tar.gz archives.