SciDaVis - SciDAVis is a free application for Scientific Data Analysis and Visualization.
GnuPlot - Gnuplot is a portable command-line driven interactive data and function plotting utility.
OriginLab - OriginLab is a data analysis tool that provide the engineers and scientist with the technical charts and system for 2D and 3D plotting and all kind of fitting including curve and peak fitting.
Dr. Geo - Dr. Geo, a software to design & manipulate interactive geometric sketches.
IGOR Pro - Technical graphing and data analysis for Macintosh and Windows.
Giac/Xcas - Free computer algebra system