Mathematica, Wolfram Alpha, GeoGebra, Desmos, Google Calculator, GnuPlot, python(x,y), Graph Toy, Graphtoy, PCalc, Golden Software Grapher, fxSolver, Graphmatica, NumWorks Graphing Calculator, Matplotlib, GeoGebra Graphing Calculator, Lybniz, GeoGebra CAS Calculator, GrafEq, Core Plot, Functy are some alternatives to Grapher.