Feels like a security issue to me. You could put in literally anyone's email address on a site that does this and immediately know if they have an account there or not. Even if you don't know their password, you know something new about that person.
I feel you on all these other ones too. There's a lot of UI/UX designers out there that need to be barred from that field forever.
Not really super well know ones, but:
Marianas Trench - Masterpiece Theatre album has Masterpiece Theatre I, II, and III on it. My favorite album of theirs. The songs from this album actually permeate the rest of their albums after this one.
Sleeping With Sirens - If you were a movie, this would be your soundtrack. A five part musical of sorts that's really well done.