Graph - Graph is an open source application used to draw mathematical graphs in a coordinate system.
Core Plot - Cocoa plotting framework for OS X and iOS
Grapher - Put Grapher’s powerful graphing and data analysis features to the test and better understand your data. Learn about features and download a free trial.
PNChart - PNChart is a chart lib used in Piner and CoinsMan for iOS.
GnuPlot - Gnuplot is a portable command-line driven interactive data and function plotting utility.
SwiftCharts - i-schuetz - Easy to use and highly customizable charts library for iOS