Xtreme Kool Letterz demands that certain letters are used. X and Z are generally considered the coolest of them all, which can lead to people forgetting all about the poor overlooked middle child: Y. Y is Y forgotten? Maybe it's a case of lost/mistaken/confused or dual (consonant or vowel) identity. Maybe it's a case of All the other Letters. But one thing is for sure: people don't like Y and we don't really know Y. Can apply to a Lettered Sequel.
- In Mega Man X, they have X and Zero (possibly for reasons related to the Japanese symbols for "right" and "wrong").
- The Powerpuff Girls gives an upgrade to Chemical X... Chemical Z!
- Pringer X gets upgraded straight to Pringer Z, too.
- This funny Flash animation: Sometimes Y
- There's Gundam X and Zeta Gundam (And Gundam ZZ), but no Gundam Y. Until a contributor who goes by the name Gundam Y is in TV Tropes!
- Averted in Yu-Gi-Oh! with Y-Dragon Head, part of XYZ-Dragon Cannon and its upgraded form VWXYZ-Dragon Catapult Cannon. Averted again in the card game with the Worm archetype. There's one for each letter, starting with Worm Apocalypse and ending with Worm Zero. Worm Xex and Worm Yagan are the only two worms designed to specifically interact with each other, and are even shaped like their respective letters, something not true of any other Worms.
- Averted with Pokemon Y Version, which is accompanying Pokemon X Version.
- Averted in Star Fox, which has the stages Sector X, Sector Y, and Sector Z.
- Johnny Test: Ms. X and Ms. Z
- Monster Hunter: G Rank armors are marked with X for the main species of the monster and Z for the subspecies. For example, G Rank Lagiacrus armor is "Lagiacrus X" and G Rank Ivory Lagiacrus armor is "Lagiacrus Z". And then Abyssal Lagiacrus (which is a G Rank monster to begin with) gets a different name altogether.
- Played with in the Phineas and Ferb episode, "For Your Ice Only". Phineas and Ferb play an extreme version of Hockey named "Hockey Z-9", the name of which is similar to another game they played "Football X-7"note . When asked why they skipped "Y-8", they replied that they were saving it for croquet.
- Defied in Y: The Last Man, in which the letter Y (as in "Y chromosome" among many other symbolic meanings) is used as a major motif. The protagonist's name is Yorick (as in "alas, poor") but it doesn't end there. In the epilogue, Yorick Prime (88 years old) manages to escape from the faculty held by his daughter, the future President of France. His straitjacket was blown away in a Y shape.
- This is literally the title of Ringo Starr's 2010 album.