Cura - Cura aims to be a end solution for personal 3D printing with RepRap based machines.
Slic3r - STL-to-GCODE translator for RepRap printers Here comes Slic3r! Its features are: - speed
MatterControl - MatterControl is a free, open source app that lets you organize and manage your 3D prints.
OctoPrint - OctoPrint is the snappy web interface for your 3D printer that allows you to control and monitor all aspects of your printer and print jobs, right from your browser.
IceSL - Welcome to IceSL!
FreeCAD - An open-source parametric 3D modeler