And no, I don't mean pop stars who snatch credits by changing two letters in another artist's original song; or those who claim it's "personal" and THEY "wrote" it, yet it's somebody else's.
I mean, those who write majority of their music and lean towards pop rock/piano rock, alternative, folk, rock -- e.g. OneRepublic/Ryan Tedder, Sara Bareilles, Jon McLaughlin, John Mayer, Ed Sheeran, Sufjan Stevens, etc.
That's the kind of music I mostly listen to, so I'm curious. I love Beyonce though and the 'I Am...' side of her third album is what I'm most in love with (of all her material), except for one thing which I won't discuss here.
My top faves write all of their music by themselves. It's just a coincidence though, cause how the music came to be doesn't affect how much I enjoy it.
I like those you mentioned, OneRepublic, John Mayer and Ed Sheeran. I enjoy listening to their music, but it doesn't really have to do with them being singer-songwriters.