Since 2010, this singer/songwriter/producer has quietly helmed some of the biggest cuts in hip-hop, R&B and pop. As co-writer, Dean helped kick up the sass in Mary J. Blige's “The One” and guided Christina Aguilera and Nicki Minaj through the libido-boosting, electro-dancehall track "Woohoo”. She's even helped out the boys: Check out her raw, Rihanna-esque pipes on Machine Gun Kelly's "Invincible".