^^ Ooooh! Jessica Stam, definitely. She has once said that "I guess I'm his muse," she has said of her mentor, Steven Miesel. He discovered her when she was 16 and cast her in "every ad campaign of his", letting her emerge as a star.
And according to wikipedia, he basically "discovered" Linda Evangelista, letting her reach stardom when she dyed and cut her hair and etc etc.
He also put James Rousseau, Heather Bratton (RIP, Heather baby.)
Maybe Karen Elson as well, because he was the one who persuaded her to shave off her hair & eyebrows...
Stella Tennant, Lily Donaldson (he cast her for LOADS of eds!!!)... Elise?
I'm sure there are many more, I just can't think of more at the moment.