Stereonet with Google Earth link, Fault slip analysis (FaultKin), trishear (FaultFoldForward), StrainSim etc. for Mac and Windows by Rick Allmendinger.
Nestor Cardozo's Stereonet3D and other programs for the Mac
Stereonet3D (Spherical projections with 3D view and export to Google Earth), GeoCalc (Vectors and tensors calculator), SSPX (strain modelling from displacement/velocity data), Trishear3D (3D forward fault related folding)
Orient: Fred Vollmer's excellent plotting program
Frederic Vollmer'splotting software: Spherical projections and fault slip and spacial analysis combined in one application.
Visible Geology (stereonet)
Stereo plotting program (web-based) with a nice 3D option. Also check out the other excellent 3D programs of Visible Geology.
InnStereo
Open-source stereographic projection program (or stereonet program) for structural geology Currently not for OSX.
GeoShear
Strain program written by Chris Warren and Paul Karabinos at Williams College. Java, all platforms.
Great programs for strain analysis and plotting in Flinn diagram, Hsu diagram and more. Requires Mathematica™. By Matty Mookerjee.
Two useful program written by Jiri Rez for Windows.