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.
A360 VIEWER - Free online CAD Viewer
de·caff Viewer - The de·caff Viewer version 3.
STP Viewer - Free STP Viewer - free software that lets you view 3D STEP files (.stp, .step file format).
Free DWG Viewer - Free Viewer for DWG, DXF, DWF View AutoCAD DWG/DWF/DXF files View & measure DWG, DXF, DWF
Glovius - Extensible & customizable 3D viewer, for consumption of product design data.