DWG FastView Plus - DWG FastView Plus is a drawing viewer that supports the fast view of many drawing formats, flexible measure, and easy share of drawings.
A360 VIEWER - Free online CAD Viewer
DWGSee - A lite and fast dwg viewer, let you view, print, markup, measure dwg files. Supports AutoCAD 2020 drawing format!
STP Viewer - Free STP Viewer - free software that lets you view 3D STEP files (.stp, .step file format).
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.
Glovius - Extensible & customizable 3D viewer, for consumption of product design data.