1)   Free DWG Viewer 5.3.0.2
Free DWG Viewer will open and view AutoCAD DWG, DXF, DWF and secure CSF formats. Drawing files can be viewed easily with full zoom / pan / eyeglass / layering controls. The viewer can save views to JPEG, and it supports accurate snap to point

 2)   Brava! Reader 2.4.0.8
The free Brava! Reader is a free application that views & prints TIFF, PDF & CSF. Brava! Reader can also view files converted by IGC's publishing products, such as the Net-It® Now client-side publisher.