- Olo
- Oltre il campo di grano
- Olverston Grange ...and Other Stories
- Olvidada
- Om nooit te vergeten
- Ombra
- Ombra Di Morte
- Ombra di morte
- Ombra Di Morte (Legami Di Sangue - Volume 8)
- Ombra tra le ombre
- Ombra. Una parabola
- Ombre
- Ombre blanche
- Ombre senza tempo
- Ombres
- Omega
- Omega Days - Die letzten Tage
- Omega Haunted Harem
- Omertà
- Omicidi al chiaro di luna
- Omnes Gentes Phobia Obscura
- Omnivore
- Omvänd (Bok #1 i Vampyrjournalerna)
- On a little street in Singapore
- On an Odd Note
- On Dark Wings: Stories
- On Dracula
- On Full Moon Night
- On Good Authority
- On Gravedigger Road
- On Hallow's Eve
- On Jack Thayer's Watch
- On Life in Prison: Survivor Chronicles
- On Ne Meurt Que Deux Fois
- On Sundays, She Picked Flowers
- On the Bloodstained Shore of Dreams
- On The Devil's Playground
- On the Night Border
- On the Road to Sibiu
- On The Third Day
- On the Verge of Madness
- On Tour For Life
- On Unfaithful Wings
- On Unnatural Authority
- On Wings of Gargoyles
- Once
- Once After Death
- Once After Death: Diary
- Once After Death: E-Story Kapitel 1
- Once After Death: E-Story Kapitel 2
- Once After Death: E-Story Kapitel 3
- Once After Death: E-Story Kapitel 4
- Once After Death: Origin
- Once Bitten
- Once Distant
- Once in a Blood Moon, A Werewolf's Tale
- Once upon a Dead Gull
- Once Upon a Dead Gull
- Once upon a Nightmare
- Once Upon A Nightmare: The Undead Tale of Sleeping Beauty
- Once Upon a Nightwalker (A Z-Tech Chronicles Story)
- Once Upon A Time In Australia 2: Before The Dreamtime
- Once Upon a Vow
- Once Upon a Winter: A Folk and Fairy Tale Anthology
- Once Upon a Zombie Apocalypse: Episode 2
- Once Upon a Zombie Apocalypse: Jade
- Once Upon a Zombie Apocalypse: Kylee
- Onde cantam os pássaros
- Onder de huid
- Ondskabens hotel
- One
- One Blessing, Two Curses: Of Vampires, Maidens and Bunnies
- One Bloody Thing After Another
- One Buck Horror
- One Buck Zombies
- One Bullet
- One by One
- One Cold December Night
- One Creepy Clown
- One Dark Night
- One Dark Summer Night
- One Evening at the Club
- One Foot and the Grave
- One Foot In Front of the Other
- One Foot in the Grave-A Holiday Short Short Story
- One For The Road
- One Foot in the Grave-A Holiday Short Short Story
- One For The Road
- One Hand Screaming
- One Heartbeat Past Normal
- One Helluva Drop
- One Hundred
- One Last Delivery
- One Last Kiss, My Darling
- One Last Nightmare
- One Last Time
- One Late Afternoon in Lower Alabama
- One Morning, A Chest
- One Night In Copan: Chronicles of Madness Foretold, Tales of Mystery, Fantasy and Horror
- One Night In The Murder Bed
- One Night with the Shifter
- One Night With The Wolf
- One of Granny's Tales
- One Of Us
- One of Us
- One of Us Will Be Dead by Morning
- One Plus One Makes Me
- One Rainy Night
- One Saturday Night, With Angel
- One Second To Midnight
- One Step Behind
- One Summer
- One Too Many
- One Way
- One Way Home
- One Who Saw
- One-Eyed Jack
- Oneiros
- Oniria
- Only Ashes, Part One
- Only Child
- Only if Invited
- Only In Her Dreams
- Only One
- Only the Dead Know Brooklyn
- Only the Devil Is Here
- Only the Ruthless
- Onmyodo Case Files 001: Shinjuku Dead Zone