Here we go then:- George Michael (Careless Whisper, *sigh*)
Lionel Bart (As long as he needs me *sigh*)
Tim Rice (Eva's Lament *sigh*)
Lennon/McCartney (The Long And Winding Road, *sigh*)
Benny Andersson/Bjorn Ulvaeus (I Know Him So Well, Chiquitita *BIG sigh*)
TECT 2 (wrote a lot of North And South's stuff) (Breathing *sigh*)
The BeeGees (Woman In Love, How Deep Is Your Love, Heartbreaker, Chain Reaction *HUGE SIGH*)

Is that enough?? There's probably some more but I can't think of them.