CONV. - Convert YouTube video to MP3, GIF or MP4
ByClick Downloader - ByClick Downloader (Former YouTube By Click) is a video downloader software for Windows. (Former YouTube By Click) Supported sites: YouTube, Dailymotion, Vimeo, Facebook, Instagram, Twitter, Pinterest and +40 site
Downie - Video download for OS X. Downie supports at this moment over 1,000 different sites.
deturl.com - How to download YouTube videos for fair rights use. No software required. Support for DailyMotion, Vimeo, and FaceBook. Save as MP3 music.
Yout - YouTube to Mp3 Converter
Freemake Video Downloader - Freemake Video Downloader downloads videos from more than 10,000 sites. Absolutely FREE. Download YouTube in HD, MP4, MP3. **Voted best of 2018**.