Re: What episode is the most unreferenced?
How about "The Man Trap"? With the possible exception of Trelane's stuffed-and-mounted salt vampire (that was probably just a budgetary thing), the only thing I can think of that references it, whether on screen or in print, is my own student short story, Inteview with Dr. Ambrose Crater, or "The Salt Vampire Ate My Parents."
Genetically modified salt vampires, designated Species M-113, are featured in a zombie-like invasion of a Romulan mining colony in the Hfihar system, in Star Trek Online
, since Season 8
1.000 years: University Leipzig, 1409-2409
Gorn to be wild!