A dark horse

A dark horse is a little-known person or thing that emerges to prominence.

• Jimmy Carter, elected the thirty-ninth president in 1976; in the beginning of that same year, Carter was relatively unknown outside his home state of Georgia but went on to win the nomination over rivals with more national prominence 

In addition, surprising or unlikely nominations for such prizes as the Academy Award (awarded by the Academy of Motion Picture Arts and Sciences) are referred to as dark horses. 

Guitarist and singer-songwriter George Harrison was nicknamed the "dark horse" of The Beatles, as his visibility as a songwriter and vocalist increased later in the Beatles' career, particularly on Abbey Road. Harrison went on to name his solo label Dark Horse Records and release both an album and a song named "Dark Horse."

"Dark Horse" is the third single from Katy Perry's third studio album, Prism.

Dark Horse is the name of the sixth studio album recorded by Canadian rock band Nickelback.^[12]

"Nickelback Discography, official band website. 

The fourth largest comic book publisher is called Dark Horse Comics.

"Imagine a technology that could preserve our freedom to choose for ourselves and our families, to express these choices in the world, and to control our own destiny, no matter where we lived or were born. What tools and jobs could we create with those capabilities? What new business and services? How should we think about the opportunities?" 
-- Don Tapscott and Alex Tapscott, Blockchain Revolution, How the Technology behind Bitcoin is Changing Money, Business, and the World You Don't Know What You Don't Know - Noam Chomsky