10. Emblem3: 21 Under 21 (2013)
Last Year's Rank: N/A
Ages: Drew Chadwick, 20; Wesley Stromberg, 19; Keaton Stromberg, 17
Why They're Hot: The "X Factor" finalists have become of the bigger reality competition success stories in recent years, as Emblem3's debut album, "Nothing To Lose," scored a No. 7 debut on the Billboard 200 chart this summer, the best bow for any alum of the U.S. "X Factor." The pop-punk trio of Drew, Wesley and Keaton have worked with Max Martin, Savan Kotecha and Good Charlotte's Joel and Benji Madden to enhance the catchiness of singalongs like "Chloe (You're The One I Want)," and have scooped up more pop fans while opening for Selena Gomez. Emblem3 will be touring relentlessly in 2014, so get ready for the number of Emblemers to multiply worldwide in no time.