LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
FreeCAD - An open-source parametric 3D modeler
QCAD - QCAD is an application for computer aided drafting in 2D.
SolidWorks - Dassault Systèmes SolidWorks Corp. develops and markets 3D CAD design software, analysis software, and product data management software. SolidWorks is the leading supplier of 3D CAD product design engineering software.
SketchUp Make - SketchUp Make is a best in the class CAD software capable of performing 2D and 3D rendering and designing, however, best for the 2D projects.
OpenSCAD - OpenSCAD is a software for creating solid 3D CAD objects.