Core Plot - Cocoa plotting framework for OS X and iOS
LabPlot - LabPlot is a KDE-application for interactive graphing and analysis of scientific data.
PNChart - PNChart is a chart lib used in Piner and CoinsMan for iOS.
SciDaVis - SciDAVis is a free application for Scientific Data Analysis and Visualization.
SwiftCharts - i-schuetz - Easy to use and highly customizable charts library for iOS
DataMelt - DataMelt (DMelt), a free mathematics and data-analysis software for scientists, engineers and students.