Graph is described as 'Open source application used to draw mathematical graphs in a coordinate system. Anyone who wants to draw graphs of functions will find this program useful. The program makes it very easy to visualize a function and paste it into another program' and is a Calculator in the education & reference category. There are more than 25 alternatives to Graph for a variety of platforms, including Windows, Mac, Linux, Web-based and BSD apps. The best Graph alternative is R (programming language), which is both free and Open Source. Other great apps like Graph are SageMath, Matplotlib, GeoGebra and GnuPlot.
Similar in scope and functionality.