X Ambassadors
Songs: Sucker for Pain - Unsteady - Renegades - Happy People (& Teddy Swims & Jac Ross) - Blinding Lights

X Factor
Joe McElderry, Leon Jackson, Same Difference, The X Factor Finalists, Alexandra Burke, Steve Brookstein, Shayne Ward, Leona Lewis, Susan Boyle, Jedward, Maria Lawson & Cher Lloyd
Songs: Hallelujah (Alexandra Burke) - Somewhere Over The Rainbow (Shayne Ward) - The Climb (Joe McElderry) - That's My Goal (Shayne Ward) - A Moment Like This (Leona Lewis)

Xanadu (film)
Music from the Motion Picture (1980)
See also: Xanadu (musical), Olivia Newton-John, Cliff Richard & Electric Light Orchestra
Songs: Suddenly (Olivia Newton-John & Cliff Richard) - Magic (Olivia Newton-John) - I'm Alive (Electric Light Orchestra) - Xanadu (Olivia Newton-John & Electric Light Orchestra) - Whenever You're Away from Me

Charli XCX
Charlotte Aitchison
Songs: party 4 u - Yuck - Guess (feat. Billie Eilish) - Talk Talk (feat. Troye Sivan) - The Girl, So Confusing (version with Lorde)

Xscape
Songs: My Little Secret - Just Kickin' It - The Arms of the One Who Loves You - Tonight - Do You Want to

Xtreme
Songs: Te extraño

XXXTentacion
Songs: Moonlight - Again (& Noah Cyrus) - Hope - Sad! - Changes