LibreTube - uses Piped as video source by default. Subscriptions and playlists can be created, all without actually interacting with YouTube.
Clipious - uses Invidious as the video source. Also allows for subscribing and accounts. Lesser known client
NewPipe - Gets the source directly from YT. Allows for subscribing and creating playlists
Additionally, there’s also ReVanced that lets you patch the regular YT app to include useful features.
It’s good and everything (although it was a bit rough around the edges here and there), but is a no-go for me personally, unless they’ve changed their license. When I last checked it wad not open source, but merely source available since the license basically said you’re not allowed to modify the source code period. AGPL would’ve been a far better choice