Matplotlib is described as 'matplotlib is a python 2D plotting library which produces publication quality figures in a variety of hardcopy formats and interactive environments across platforms' and is an app in the Development category. There are more than 25 alternatives to Matplotlib for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and iPhone. The best alternative is GeoGebra, which is free. Other great apps like Matplotlib are MATLAB (Paid), Plotly (Freemium, Open Source), GnuPlot (Free, Open Source) and Microsoft Mathematics (Free).
Is a powerful, easy-to-use, equation plotter with numerical and calculus features: Win32 screen shot. Graph Cartesian functions, relations, and inequalities, plus polar, parametric, and ordinary differential equations. Up to 999 graphs on screen at once.
Gadfly is a system for plotting and visualization written in Julia. It is based largely on Hadley Wickhams's ggplot2 for R and Leland Wilkinson's book The Grammar of Graphics. It was Daniel C. Jones' brainchild and is now maintained by the community.