DWGFREE - DWGFREE is an online platform that comes with a comprehensive collection of CAD blocks that can be downloaded without the need for registration.
STP Viewer - Free STP Viewer - free software that lets you view 3D STEP files (.stp, .step file format).
CADMAPPER - Instant CAD files for any location on earth
A360 VIEWER - Free online CAD Viewer
Cadbull - Cadbull is a website that comes with an advanced collection of CAD blocks and DWG design, facilitating architects and designers to get done with their projects efficiently.
Glovius - Extensible & customizable 3D viewer, for consumption of product design data.