GnuPlot - Gnuplot is a portable command-line driven interactive data and function plotting utility.
Portable Python - Minimum bare bones portable python distribution with PyScripter as development environment.
GeoGebra - GeoGebra is free and multi-platform dynamic mathematics software for learning and teaching.
WinPython - The easiest way to run Python, Spyder with SciPy and friends out of the box on any Windows PC...
SciDaVis - SciDAVis is a free application for Scientific Data Analysis and Visualization.
Anaconda - Anaconda is the leading open data science platform powered by Python.