Mathematics WWW Virtual Library
NIST Guide to Available Mathematical Software
Wikipedia List of numerical analysis software
Exponenta.ru (Softline, 2004)
Community Portal for Automatic Differentiation
Mathematica - universal mathematical environment (can do anything)
Matlab - numerical mathematical environment
Octave - high-level interpreted language for numerical computations
Form - A program for large scale symbolic manipulation
Comsol Multiphysics - numerical solver of partial differential equations
Statistica (Statsoft)
SPSS packages
NCSS - statistics and data analysis
Programs for calculating Feynman diagrams: DiAna, xloops
Maxima, Reduce - manipulation of symbolic and numerical expressions
Cuba - a library for multidimensional numerical integration
Origin - standalone tool for plotting functions and visualizing data
IDL - Interactive Data Language