yt-dlp - A youtube-dl fork with additional features and fixes.
y2mate.tv - Y2Mate YouTube Converter is not just a video converter, but also an audio converter. You can easily convert YouTube videos to the format you want, such as MP4 (320p, 480p, 720, HD 1080p), 320kbps MP3, M4A, WEBM, etc.
ytbtomp4 - Ytbtomp4 is a free and safe YouTube downloader helping users convert YouTube videos to MP4 and MP3. Easy to use.
Savemp3.cc - An online free YouTube converter which allows you to convert videos and audios to MP4, MP3, M4A from YouTube, Facebook, Instagram, MixCloud, Dailymotion, VEVO, bilibili, niconico, etc. Supports HD MP4, 720p, 1080p video and 320kbps MP3.
NewPipe - NewPipe is a lightweight YouTube front-end for Android.
YTMP3.co.com - YTMP3.co.com is a 100% free multi-format audio and video downloader that lets you convert video and audio from most social media platforms. No annoying ads.