GnuPlot - Gnuplot is a portable command-line driven interactive data and function plotting utility.
GeoGebra CAS Calculator - Free online algebra calculator from GeoGebra: solve equations, expand and factor expressions, find derivatives and integrals
GeoGebra - GeoGebra is free and multi-platform dynamic mathematics software for learning and teaching.
SciDaVis - SciDAVis is a free application for Scientific Data Analysis and Visualization.
Dr. Geo - Dr. Geo, a software to design & manipulate interactive geometric sketches.
Grapher - Put Grapher’s powerful graphing and data analysis features to the test and better understand your data. Learn about features and download a free trial.