Invidious mainly, and that doesn't use any YT accounts, it's the equivalent of watching YT logged out.
Also, Grayjay lets you log in through it but that probably doesn't bypass the age check if you're KYC'd.
If you're an active creator yourself though or even if you only have a few vids you made years ago that are still up, I'd set up PeerTube, Odysee, or both, and post those there while you still can, though.