Swedish songwriter and uber-producer Shellback is responsible for some of the biggest pop hits of the ‘10s, his background in metal lending his songs a searing, percussive urgency. He builds beats into wildly satisfying crescendos, as on Maroon 5's “Moves Like Jagger” and Taylor Swift's “Shake It Off,” and lends unabashed rock moxie to huge pop bangers, like P!nk's “Raise Your Glass.”