FreeCAD - An open-source parametric 3D modeler
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
SketchUp - 3D for Everyone
SelfCAD - SelfCAD is an online 3D modeling and slicing software.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
Autodesk AutoCAD - Autodesk AutoCAD is a commercial computer-aided design (CAD) and drafting software application.