I'm so honored that @Nicholas requested this list from me. I have decided, in the interest of making the most comprehensive list, to include any person from any time. The context of the show, as a series on air from 1989-1998, remains the same, but let's imagen that some of these cameos could have existed regardless...
  1. Drake
    Drake is the ultimate Seinfeld cameo. There can only be one true The Drake, and he is it.
  2. Disgraced NY governor Elliott Spitzer
  3. Leslie Mann
  4. Michael Jordan
  5. Post-Olympics Nancy Kerrigan
  6. Phil Hartman in character as Ted from Jingle All the Way
  7. Olivia Munn
  8. Adam Pally
  9. Elizabeth Hurley (seriously how did this not happen?)
  10. Any of the following Real Housewives: Jill Zarin, NeNe Leakes, Kyle or Kim Richards
  11. John Slattery
  12. Triumph the Insult Comic Dog
  13. Gillian Jacobs