LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
FreeCAD - An open-source parametric 3D modeler
MacDraft - MacDraft Professional, powerful 2D CAD, drafting, technical illustration, architectural drawing and...
SketchUp - 3D for Everyone
ImplicitCAD - ImplicitCAD is a programmatic CAD program, implemented in Haskell.
Autodesk AutoCAD - Autodesk AutoCAD is a commercial computer-aided design (CAD) and drafting software application.