Great Downloader easy to use can convert into multiple file formats. Fast and impressive
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.
Video DownloadHelper - Browser extension to download videos from the Web
Autodesk Design Review - Design Review lets you view, mark up, print, and track changes to 2D and 3D files.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
ZWCAD Viewer - Cross-Platform .DWG | .DXF | .DWT R12-2013 Viewer
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.