Vampires are just generally compelling. In D&D, there’s quite a few things they do that feel very right; unfortunately, by hitting “vampire” square in the center of the target, the game removes some of the flexibility of the archetype. Let’s put it back!
Things I like that are core: Vampires are twisted and hungry: they have a bite attack which drains the victim and sustains the vamp, and a list of taboos which prohibit action or deal them damage. They use their bite to breed vampire spawn, a simpler monster which shares these traits (though sadly, can’t breed; vamps can up-convert their spawn, but then they become free willed). Vampires themselves have other forms (bats, mist clouds) and can use them to cheat death.
The big themes here: Sunlight. Running water. Blood. Thresholds. Piercing weapons made of wood to the heart (but only while incapacitated). Seduction. Creatures of the Night (calling, becoming; bats, rats, mist, even wolves).
Things to note: There’s nothing special about holy symbols repelling vamps. Turn undead or GTFO. Garlic has no effect, or even mention. It’s not clear how to sanctify a vampire’s resting place; I’m sure magic circle or forbiddance could hedge out a vamp, but it’s not clear whether you could fake it with an aspergillium and a tank of holy water. I suspect not! Killing a vampire within 2 hours of its resting place requires staking it while incapacitated and then dragging the assemblage into sunlight or running water, since other sequences of events trigger its dying-mistform state. Or slay it and then use a shopvac. The Dracula myths don’t make as much of the wooden stake as the game rules do; another Bram Stoker short story has a similar vampire paralyzed with an iron bar through the heart, and in general I’m willing to allow any sort of transfixion to work, so long as it literally pins the vamp in place.
The nature of the vampiric curse is centered on their heart. That’s what the transfixion relies upon, somehow: a pierced heart is held in place, and prevents the vampire from using their shapeshifting to escape it. If we start from there and move outwards, we could impose material restrictions on what can transfix the vamp in place; this kind of vampire needs lignum vitae stakes and this one a piece of glass and this one copper tubing and this one a javelin of lightning and so on. That actually doesn’t interest me, though; like I said upthread, I think focusing on the material from which the stake is made is a mistake, folklorically.
For clarity, the vampire we have on the books now is the Dracul Vampire, continuing the theme of naming a monster after the individual instance. The resonance of Vlad Dracul, the dragon, being the Dungeons and Dragons platonic vampire is just too good for me to pass up. So where did this Dracul “bloodline” come from? We know that Strahd is the result of the Dark Powers and it’s not unreasonable to assume a similar source for the case of Vlad Tepes, Dracula’s historical counterpart. The bat connection seems particularly strong; perhaps Dracul (Draculi? Draculs?) are the spawn of some bat-aspected death power, like Camazotz. The linkages to sacrifice and night are great, as is the link to the Vargouille or Penanggalan, with the ripped-off-head thing. Tying that power to the forbiddance of a threshold, with the threshold between day and night, life and death, home and wild — that’s pretty interesting to me.
This cluster of behaviors, substances and taboos fascinates me because, absent folklore, there’s nothing to tie them together. Yes, dawn is a natural dividing line between fear of the dark and safety; yes, a threshold represents that same division between home and the wilds; yes, a heart would be important to a creature sustained by blood. But all three, and the strength of those mythic ties? There’s more here. Obviously.
So let’s have at it.
Another potential vampiric line might hold no fear of the sun nor of water, such as ocean-based vampires. Instead, they are ruled by the tides and by salt. They suffer Dracul-like sunlight exposure on dry land at low tide (unless they are immersed in water), and Dracul-like running water exposure when exposed to at least 1 pound of salt crystals; additionally, they are unaffected by holy water, but are affected equivalently by salt. Thresholds hold no fear for them, but rigging lines do, and if captured in a fishing net in their place of rest, they cannot transform. Their form associations are not with mist/bats/rats/wolves but pooled dark water (with climb speed!)/water serpent/shark. Some hungry deity of the deep such as Dagon or Hydra is their patron, and their alignment is chaotic evil.
We might replace their charming gaze with a charming call, since these vampires are shaping up to a sort of siren. But the as-written gaze works fine too. Optional.
The Indian vetala gives us another vampire: it is its mist form and is capable of inhabiting any corpse; destroying its shell forces the mist to depart, reform, and then seek a new corpse-shell. Wikipedia gives us no further details, so I shall now free-associate. I want to differentiate these misty beings from our Dracul, so I shall say that they are bound not by sunlight, but by scent. They lose their sunlight hypersensitivity. Instead, they gain a scent hypersensitivity; while they are exposed to any domestic smell (incense, fresh bread, garlic, herbs, cookfires, hay, petrichor; not to include an adventurer’s burning oil, torch, trash fire or offal), they are affected as though a Dracul by sunlight. Additionally, they are unaffected by holy water, but are affected by scented oils or perfumes. They retain their susceptability to running water and to thresholds. They lose their charm gaze, replacing it with a fear gaze; while frightened, the target is paralyzed. I like the idea of their “mist form” being truly an “ash form”, as they’re cremains; with that principle, their animal association might be with beetles.
The oneiric vampire is a different sort of beast, but we can think of it like a vampire. It’s a sort of haunting or psychic projection of an otherwise inanimate corpse which must remain interred in its resting place or else the vampire is destroyed. Their “mist form” is instead an invisible, incorporeal form which, if their projected form is forced into, must reach and rejoin their corpse to rest and rejuvenate; their “animal forms” are humanoid physical alterations similar to those of a doppelganger. They do not fear sunlight, running water, nor thresholds. They do not have a charm gaze; instead, they have a sleep gaze. They do not deal nor resist necrotic damage; instead, psychic damage. Their appearance in a mirror matches their corpse, not their current form; the presence of “holy sounds” at the proper times (calls to prayer such as churchbells or muezzin, or the actual prayers at the proper times) is treated as thunder-dealing immersion in running water, and the presence of “holy symbols” a sort of muted sunlight: it deals no damage, but shuts down regeneration, altnerate abilities, and the vampiric drain itself. Direct contact with the symbol deals radiant damage. The vampire is unaffected by holy water, but may be targeted by prayer with similar effect; a recital forces a wisdom save with a DC of 8 + the wisdom of the reader, dealing thunder damage as holy water if failed, and granting immunity to that reader for 24 hours if succeeded.
The icelandic Draugr makes a decent vampire: they can take the form of wisps of smoke, swim through solid rock, devour flesh (a fine substitute for sucking blood), and can drive foes mad, though do not seem to retreat to their place of rest. Instead, if destroyed, they rejuvenate unless their corpse is treated correctly. In any case, they have a confusion gaze in place of charm. They tend to remain in their barrows; they can enter any place that has even a single coin of their treasure (but are otherwise pent by thresholds); they can take on any animal forms with challengeless than their own challenge, even the spawn forms have this ability, and they tend to have a variety of magical powers atop this (darkness, etc — spellcaster variant vampires would be good enough). The spawn might be called “haugbui”, a lesser form. They have no especial fear of water (indeed, they were often drowned fishermen). It is by no means clear that they have sunlight hypersensitivity either, though their nocturnal-only activity points in that direction.