Though these seven artists didn't make this year's 21 Under 21 ranking, they're worth keeping an eye on as they capitalize on their momentum, from an unexpected smash-hit collaboration to a protest song that arrived when the country needed it most.
Holly Humbersone: This 20-year-old independent British singer-songwriter scored a breakout hit with “Falling Asleep at the Wheel,” the title track to her debut EP.