X Ambassadors
Songs: Boom - Renegades - Home (& mgk & Bebe Rexha) - Sucker for Pain - 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) - You'll Never Walk Alone (Ray Quinn) - Somewhere Over The Rainbow (Shayne Ward) - When You Believe (Leon Jackson) - Heroes (The X Factor Finalists)

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

Charli XCX
Charlotte Aitchison
Songs: New Shapes (& Christine and the Queens & Caroline Polachek) - Apple - Guess (feat. Billie Eilish) - Sympathy Is a Knife - I Love It (& Icona Pop)

XG (エックスジー)
Also known as 엑스지
Songs: Woke Up - Shooting Star

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

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

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