LinuxCNC (the Enhanced Machine Control) - LinuxCNC: an open source CNC machine controller. It can drive milling machines, lathes, 3d printers, laser cutters, plasma cutters, robot arms, hexapods, and more.
Sketch - Professional digital design for Mac.
PyCAM - PyCAM is a toolpath generator for 3-axis CNC machining.
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Mach3 - Mach3 is very popular among the Hobby CNC community.
Affinity Designer - Professional creative software, exclusively for Mac.