Universal Gcode Sender - A full featured gcode platform used for interfacing with advanced CNC controllers like GRBL and TinyG.
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.
bCNC - Development
Vectric Aspire - The complete software solution for CNC Routing,
Candle - GRBL controller application with G-Code visualizer written in Qt
Mastercam - Mastercam's Dynamic Milling is a game changer for us.