X Ambassadors
Songs: Boom - Unsteady - Sucker for Pain - Happy People (& Teddy Swims & Jac Ross) - Jungle (Remix) (& Jay-Z)

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) - The Climb (Joe McElderry) - When You Believe (Leon Jackson) - Summertime (Leona Lewis live) - Somewhere Over The Rainbow (Shayne Ward)

Xanadu (film)
Music from the Motion Picture (1980)
See also: Xanadu (musical), Olivia Newton-John, Cliff Richard & Electric Light Orchestra
Songs: Magic (Olivia Newton-John) - Xanadu (Olivia Newton-John & Electric Light Orchestra) - All Over the World (Electric Light Orchestra) - Don't Walk Away (Electric Light Orchestra) - Whenever You're Away from Me

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

XTC
Songs: Dear God - Senses Working Overtime - Making Plans for Nigel - Mayor of Simpleton

XTM
Also known as Xasqui Ten & Toni Ten
Songs: Fly on the Wings of Love (& DJ Chucky & Annia)

XXXTentacion
Songs: Moonlight - Again (& Noah Cyrus) - Fuck Love (& Trippie Redd) - Hope - Falling Down (& Lil Peep)