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