Ships that never sailed, fetishes still fettered. To the best of my Googling, no one has ever made or wanted pornography involving the following subjects:
  1. Anthropomorphic exercise balls
  2. Besson, Luc
  3. Cookie Crisp (the cereal itself; obviously the mascot has an extensive speculative porn portfolio)
  4. Dandy Warhols, just kinda petting each othet
  5. E. Coli reproducing asexually
  6. Fat Boy Slim and the Mighty Dub Katz
  7. Gene Autry "Back in the Saddle"
  8. Hellmouth (Buffy)
  9. Ingmar Bergman's Magic Flute
  10. Jumping Joe Dugan of the 1922 Red Sox
  11. Ketosis dieting
  12. Lorne Michaels
  13. Mr. Mister full-band orgy
  14. Namaste, just the word itself
  15. Ode to Joy and Pachelbel's Canon in D just going at it, holding each other in suspension
  16. P - See above
  17. Quorn meat substitutr
  18. Razzie Awards, the statuettes berrying each other
  19. Sopaipilla, feederism stuff with one sopaipilla "shortening" another one
  20. The T-Zone on my face
  21. Unununium alpha decaying
  22. Video killing the radio star (snuff)
  23. Wooden, Coach John
  24. Xzibit's album art, mosaic-ed into sex stuff
  25. Yo La Tengo
  26. Ziti getting baked and going to town on Penne