X Ambassadors
Songs: Renegades - Unsteady - Home (& mgk & Bebe Rexha) - Boom - Sucker for Pain

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) - A Moment Like This (Leona Lewis) - The Climb (Joe McElderry) - Somewhere Over The Rainbow (Shayne Ward) - Wild Horses (Susan Boyle)

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) - Xanadu (Olivia Newton-John & Electric Light Orchestra) - I'm Alive (Electric Light Orchestra) - All Over the World (Electric Light Orchestra)

Charli XCX
Charlotte Aitchison
Songs: Guess (feat. Billie Eilish) - I Love It (& Icona Pop) - party 4 u - 365 - Sympathy Is a Knife

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

Xtreme
Songs: Te extraño

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