YouTube music still lacks a few features compared to other streaming services, especially its predecessor Google Play Music. It is slowly improving as things are added and bugs are fixed, though. One of the more annoying aspects of YouTube Music is how your library is handled, but Google is now testing a Library Tracks playlist that should go some way to ease the issue.
Reddit user u/Iordbrack spotted the new playlist over the weekend, and it pretty much does what the name tells you. The playlist will show every song in your library regardless of whether it's been liked or not. One benefit is that you can easily download your entire library in one go. Do that, and you'll effectively have all of your playlists available offline, even if you haven't downloaded them individually.
Image Credit: u/Iordbrack
Sadly, there's one major caveat: the music uploaded to your library isn't included. If you're a former Play Music user wanting your entire library in one place, you're still out of luck. However, this could change as this playlist is still in the testing phase, only showing up for a few users. What's more, trying to access it directly will result in a 404 error. You need to download it and set the app to offline mode to use it at present. Hopefully, as it's improved, uploaded music will be included too.
- XDA Developers