Mythological and folkloric roots of hungry dead

Zombies

Zombies originate from Haitian voodoo. Evil sorcerers use magic to capture the souls of the dead, reanimate their corpses and use them as labor slaves. This was especially terrifying to the Haitians: at the time they were enslaved by the colonists and thus it made sense they especially feared being enslaved after death. Haitian folklore has attributed other supernatural powers to zombies, such as transforming into smoke to get around barriers.

A similar belief appeared in Chinese culture, where funeral directors were once believed to use magic to reanimated dead bodies to make them easier to transport to their homelands where they would receive last rites. The reanimated were called 僵尸 jiāngshī meaning “stiff corpse.”

D&D zombies and skeletons are more or less identical to the Haitian zombie.

Ghouls

Ghouls originate from Arabic folklore, where they are a type of genie that haunts graveyards and consumes corpses. They are said to have traits of donkeys, like pelts, tails, hooves, and large ears.

The wendigo from the folklore of the Algonquin peoples bears similarities to the ghoul due to their carnivorous nature, though the wendigo is sometimes claimed to be a human transformed or possessed by a wendigo as punishment for cannibalism.

Ghouls appeared in some of the fiction of H.P. Lovecraft and his followers, where they were attributed to kidnap human children and replace them with their own (similar to the changeling, a European fairy) and to transform humans into ghouls through some manner of black magic (similar to some stories of the wendigo).

D&D ghouls drawn some inspiration from Lovecraft's ghouls, but are mostly conflated with the "ghouls" from Night of the Living Dead.

Vampires

In 20th century fiction and beyond, both zombies and jiāngshī would be attributed ghoul- or vampire-like hunger for the flesh or vitality of the living. Meanwhile, ghouls would be conflated with zombies as a kind of flesh-eating undead creature. These modern monsters bear more resemblance to the vampires of folklore than to the zombies and ghouls of folklore.

The modern vampire retains the hungry nature of its predecessors, but has acquired overtones of power and sexual lust. This movement started with Dracula, was refined by Interview with the Vampire, and reached its nadir in the Twilight books. That being said, the folkloric vampire has made resurgence in counter-cultural fiction.

D&D vampires are taken straight out of Dracula.