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!
yt2mp3.org - Free online YouTube to MP3 Converter
OnlineVideoConverter.com - OnlineVideoConverter.
Ytmp3.cc - By using our converter you can easily convert YouTube videos to mp3 (audio) or mp4 (video) files and download them for free - this service works for computers, tablets and mobile devices.
Tubidy - Tubidy is a popular online platform that allows users to search, download, and stream videos and music from various sources, including YouTube.
VidToMP3.com - VidToMP3.