VRR is a vector image editor designed especially (but not only) for making illustrations of mathematical articles. Its main features are many types of geometric objects and keeping of their dependencies, cooperation with TeX, scripting in Scheme, real-size dimensions, support for a wide range of file formats (including PS, EPS, PDF, and SVG).
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.
HopSlide is a tool for authoring and playing slides. It supports animations, annotations (slide overlays), math formulas (MathML support and TeX syntax support), SVG images, and canvas graphical effects. HopSlide can be used to compile slides into XHTML files. These files can be used by XHTML capable browsers (e.g., Firefox). Compiled slide files can be used to play the slides without HopSlide.