FreeCAD - An open-source parametric 3D modeler
Autodesk DWG TrueView - Get a free DWG viewer to view, open, edit, and convert .dwg files, the native file format for AutoCAD files. DWG Trueview includes DWG TrueConvert.
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.
LiteCAD - Create, edit, view, and print 2D CAD drawings using the file formats: dxf, dwg, shp ;Download-Size...
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
ZWCAD Viewer - Cross-Platform .DWG | .DXF | .DWT R12-2013 Viewer