Cura - Cura aims to be a end solution for personal 3D printing with RepRap based machines.
Unity - The multiplatform game creation tools for everyone.
Slic3r - STL-to-GCODE translator for RepRap printers Here comes Slic3r! Its features are: - speed
Godot Engine - Feature-packed 2D and 3D open source game engine.
Repetier - Software for controlling RepRap style 3D-printer like Mendel, Darwin or Prusa mendel.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.