Beyonce - Most of 4 and IASF's singles
Chris Brown - Don't Wake Me Up, Turn Up the Music, Yeah 3x
Selena Gomez - Falling Down, Naturally
Justin Bieber - As Long As You Love Me (kinda), Beauty and a Beat
Kelly Clarkson - Since U Been Gone
Katy Perry - ET
Nicki Minaj - Girls Fall Like Dominoes, Beez In the Trap (I like a lot of her pre-Pink Friday guest verses though)
Ellie Goulding - Lights
Marina and The Diamonds - Oh No
Lana Del Rey - Video Games, Blue Jeans