Looks promising. Doesn't seem to support subscriptions, though, which is the problem every unofficial YouTube app seems to have. Probably because logging in and accessing subscriptions requires the API, which has a ToS.
Yeah, the XBMC Youtube addon used to do subscriptions and the like, it was pretty nice, but I think it broke and the main developer abandoned it. Youtube-dl does support channels and resuming though so you could fairly easily just set up a cron job and use syncthing to get the videos onto your phone. No pretty GUI for that though.
I personally use an RSS Reader to handle my "subscriptions".
The YouTube-webpage also has an option to export your subscriptions to an OPML-file (which can then be imported into an RSS Reader): Log into your YouTube-account, then go to "Manage Subscriptions", and then at the bottom of that page, there's a button for it.
(This is how it worked a few months ago. I actually don't have a YouTube-account anymore, so I can't check if it still works like that.)
On Android, I personally use SpaRSS [0] with it, which does work quite well, but it being available on F-Droid was pretty much essential to me, so if you don't care about FLOSS, you might be able to find an RSS Reader which integrates even better with this setup...
By installing a custom ROM without also installing GApps. For example, I have a Nexus 6P running CopperheadOS, which doesn't include GApps (it, like CyanogenMod, supposedly supports it but makes it optional/separate from the OS itself).
There is also this app [1] (shameless plug, I wrote it) which uses youtube-dl to download videos off any supported sites. No real UI as it just parses the media URL (when a link is shared to it) and passes it off to the android download manager.
I threw it together (over a few hours) simply because I like watching stuff on youtube at 1.5x speed and the android app does not allow you to do it (whereas if you use VLC to play the downloaded video, you can increaseplayback speed)
It's also available on the play store [2] with youtube downloads disabled by default
I just tried NewPipe. However, after downloading a video, you can no longer play it directly in NewPipe (with NewPipe's ability to play in the background), only in an external player.
https://f-droid.org/repository/browse/?fdid=org.schabi.newpi...