Great Downloader easy to use can convert into multiple file formats. Fast and impressive
Video DownloadHelper - Browser extension to download videos from the Web
HTTrack - HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
WebCopy - Cyotek WebCopy is a free tool for copying full or partial websites locally onto your harddisk for offline viewing.
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.
SiteSucker - SiteSucker is a Macintosh application that automatically downloads Web sites from the Internet.