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.
And the difference there is that Vanced didn’t have capital behind it while Grayjay does. Futo can fight Google in court, Vanced couldn’t. Even if a company has no legal ground to stand on, they can still fuck you financially with legal fees and a drawn out case.