But what's your campaign that you have never had chance to play but would love to if you could?
There are a ton.
The Great Pendragon Campaign
Beyond the Witchlight
Tomb of Annihilation
Chronicles of the Dragonlance
A thoroughly revised "Skull & Shackles"
Two-Headed Serpent
A full Ravenloft campaign based on thoroughly revised and expanded "Curse of Strahd"
My own "Return of the Ice Witch"
Revisit my own unfinished "The Green Guild of Harlond"
Revisit my own unfinished "The Goblin Campaign"
Finish my own "Esoteric Order of the Golden Globe"
Finish my own (current) "Tales of the Dogfish"
Gamma World for nostalgias sake using a D20 modern based system.
A Star Trek campaign using the rules for Dogs in the Vinyard.
A Star Wars "Exploration Corp" game set in the Old Republic that is basically Star Trek in the Star Wars universe.
A Star Wars "Survivors" campaign with the PCs all hunted Padawans in the aftermath of Order 66.
A "Tortall" campaign using the rules for Pendragon with custom cultures suitable for Tortall.
That's probably on the order of 100 years of gaming. It's not going to happen, but still.