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.
Autodesk Design Review - Design Review lets you view, mark up, print, and track changes to 2D and 3D files.
DWG FastView - DWG FastView for Windows is a lightweight dwg/dxf drawing viewer and editor produced by Gstarsoft, no need of dwg format conversion, vector graph magnified without distortion and full compatible with AutoCAD DWG/DXF.
ZWCAD Viewer - Cross-Platform .DWG | .DXF | .DWT R12-2013 Viewer
Creo View Express - Creo View Express is a simple CAD tool to review a 3D design for a quick evaluation.
AutoCAD LT - AutoCAD LT is a drafting tool to create 2D drawings.