Things that have not be put elsewhere.
Program which can be used non-interactively to be used in web applications or something else
For non-interactive applications (e.g. web) one can use R. Note that R's PNG and JPEG devices rely on having an X server present. I've had success with R producing EPS output, and then using Imagemagick's convert command, which calls Ghostscript behind the scenes, to rasterize it.
See also this
Similarly to the above, some functionalities of yorick (e.g. writing a mpeg movie using yorick-mpeg) require the openning of an X window. When I want to do it non-interactively, I use a VNC server instead of a "real" X11 display. Other "dummy" X11 servers suitable for this sort of tricks may exist. ThibautPaumard.