Great Downloader easy to use can convert into multiple file formats. Fast and impressive
Video DownloadHelper - Browser extension to download videos from the Web
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
ClipGrab - A friendly downloader for YouTube and other sites
Freemake Video Converter - Freemake Video Converter Converts 500+ Formats & Gadgets FREE! Convert to MP4, AVI, MKV, WMV, DVD, Xvid. FREE Download. **Voted Best of 2018** Comes with FREE…
yt-dlp - A youtube-dl fork with additional features and fixes.
MediaHuman YouTube to MP3 Converter - Extracts MP3 audio from YouTube, Vimeo, Dailymotion, Mixcloud, Bandcamp, SoundCloud and many others. Available for macOS, Windows and Ubuntu/Linux. FREE!