A360 VIEWER - Free online CAD Viewer
Easy CAD Viewer - Easy CAD Viewer is a web-based and complete software that allows you to view the files which are created by AutoCAD and you can view the files quickly in the absence of AutoCAD.
STP Viewer - Free STP Viewer - free software that lets you view 3D STEP files (.stp, .step file format).
ODA Viewer - ODA Viewer is a web-based software solution that allows you to view the files based on ODA format and you can easily zoom the file for detail visualization.
Glovius - Extensible & customizable 3D viewer, for consumption of product design data.
DXF View - A lightning-fast drawing viewer enables you to view DXF and DWG™ files on Mac