Blender - Blender is the open source, cross platform suite of tools for 3D creation.
FreeCAD - An open-source parametric 3D modeler
Autodesk 3DS Max - 3ds Max is software for 3D modeling, animation, rendering, and visualization. Create stunning game enrivonments, design visualizations, and virtual reality experiences.
SketchUp - 3D for Everyone
Unity - The multiplatform game creation tools for everyone.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.