YouTube2Video - Youtube to video downloader and Converter, Convert & download YouTube videos to MP3 MP4 and also convert device videos to mp3. No software download needed.
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!
Notube Youtube Converter - Notube Youtube Converter is an online video conversion tool that allows you to convert and download YouTube videos into mp3 format.
YTmp3.net - Download your favorite YouTube videos as mp3 files without registration.
Mpgun - Mpgun is an online video converter that allows you to download the YouTube video or convert it into an mp3 file and then download it.
OnlineVideoConverter.com - OnlineVideoConverter.