IRAF (Image Reduction and Analysis Facility) is a large package consisting of a command line interface to hundreds of data and image processing tasks. Extensive support for scripting and user built additions. The Space Telescope Data Analysis System is an IRAF add-on.
MIDAS is another huge package similar to IRAF. The screenshot illustrates part of the packages built-in self-test script.
NEMO is a comprehensive stellar dynamics package. The screenshots show a variety of snapshots from the output of a colliding galaxy model.
PGPLOT and it's scripting extension PGPERL (written in the perl language) provide a wealth of easily accessible data plotting and visulaisation tools.
