From ‘Notes On Weird Fiction’

4. A List of Certain Basic Underlying Horrors Effectively Used in Weird Fiction

[1.] Unnatural life in a house, and unnatural linkage of lives of separate persons.
[2.] Premature burial.
[3.] Listening for some approaching horror.
[4.] Metempsychosis—a dead being forces its personality upon the living.
[5.] Offspring of a mortal and a daemon.
[6.] Any mysterious and irresistible march toward a doom.
[7.] Unnatural life in a picture—transfer of life from person to picture.
[8.] Prolongation or persistence of an abnormal animation in the dead.
[9.] Duplication of a personality.
[10.] Ravages on a grave—discovery that the seemingly dead is alive.
[11.] Unnatural connexion betwixt an object and some image of it.
[12.] Membership in hellish cult of witchcraft or daemonolatry.
[13.] Presence of horrible hidden race in lonely region.
[14.] Shocking metamorphosis or decay of living human as induced by taking unknown and evil drug. Idea of monstrous companion.
[15.] Beasts acting deliberately against man.
[16.] Unseen cosmic presences in certain region—idea of genius loci.
[17.] Psychic residuum in old house = ghost.
[18.] Village whose inhabitants all share monstrous secret rites.
[19.] Elemental spirit intrudes or is invoked.
[20.] Holy organisation secretly goes over to diabolism.
[21.] Subtle vampiric preying of one being on another.
[22.] Terrible hermit in lonely place—preys in some way on travellers.
[23.] Powers of darkness (or cosmic outsideness) besiege or take over sacred edifice.
[24.] Hideous daemon attached to some person (& after his death to certain objects pertaining to that person) through sin, incantation, etc.
[25.] Hideous sacrifices attempted through exercise of some bygone paganism. Ghostly reprisal.
[26.] Changes in a picture corresponding to actual events (present or old) in scene it depicts.
[27.] Evil wizard employs metempsychosis to survive in animal forms and carry out revenge.
[28.] Ghostly room in house—sometimes there, sometimes not.
[29.] Wizard acquiring evil companion through trip to strange region of horror.
[30.] A pursuing thing called from the grave through an injudicious incantation.
[31.] Blast on an exhumed whistle of unknown antiquity summons vague and hellish presence from the Abyss.
[32.] Monstrous supernatural guardian set over treasure or book hidden in ancient ruins.
[33.] A dead man comes from the grave to bear off or punish his murderer.
[34.] Inanimate object acts as living thing to avenge crime.
[35.] Ghost of victim convicts murderer.
[36.] Disturbance of an ancient grave looses a monstrous presence on the world.
[37.] Magical telescope (or cognate device) shews the past when looked through.
[38.] Excavation of an ancient and forbidden thing saddles excavator with a hostile shadow, which eventually destroys him.
[39.] A household in great terror of the coming of some unknown doom.
[40.] A sacrilege toward an ancient church summons out of space or the sea an avenging monster which devours the desecrator.
[41.] Perusal of a certain hideous book or possession of a certain awful talisman places person in touch with shocking dream or memory world which brings him eventual destruction.
[42.] Man abnormally akin to lower animals. They avenge his murder.
[43.] Insect hypnotizes man and leads him to his death.
[44.] Ghostly vehicle. Man boards it and is carried into unreal world.
[45.] Sleep-walker drawn nearer and nearer to some horrible place. Tryst with dead, etc.
[46.] Body buried beneath cellar hounds murder (or injurer) to death.
[47.] In savage land, hermit priest guards old shrine containing a very strange and ancient Presence. Accident looses presence, and harm is done to person responsible.
[48.] Remote island region at extreme limit of world—Edge of Abyss. Strange horror appears there.
[49.] Ghouls of the sea that come to land in guise of seals and prey upon mankind.
[50.] Reconstruction of ancient temple or re-dedication of ancient altar evokes dangerous, unbodied forces.
[51.] Evil student reanimates mummy 4000 years old, and forces it to do his murderous bidding.
[52.] Man tries to recapture all of his past, aided by drugs and music acting on memory. Extends process to hereditary memory—even to pre-human days. These ancestral memories figure in dreams. Plans stupendous recovery of primal past—but becomes sub-human, develops a hideous primal odour, takes to the woods, and is killed by own dog.
[53.] Traveller coming upon something horrible in strange place—as a horror in a cabin with lighted window found in a forest’s depths.
[54.] Dream and waking worlds confused.
[55.] Some past (or future) horror just outside memory (or prescience).
[56.] Entire scene and set of events caused by hypnosis—proceeding either from living person or from corpse or other harbourer of residual psychic force.
[57.] Coming to unknown place and finding one has some hitherto latent memory of it, or hideous connexion with it.