- O Brindo de ouro I
- O caso da mansão Deboën
- O Chamado de Cthulhu
- O coletor de espíritos
- O escritor fantasma
- O espantalho
- O garoto pobre
- O Homem da Cartola
- O ladrão de órgãos e outras lendas urbanas
- O livro do cemitério
- O Lobo em Mim Vem de Fora
- O maior mágico do mundo
- O malvado Bicho Papão
- O piano
- O poço dos desejos
- O Presságio Vampírico
- O Reino
- O Resgate Vampiro (Telepatas vs Vampiros - Livro 2)
- O Segredo da Cidade - Um Serial Killer a solta
- O vale dos mortos
- Oath
- Oathsworn
- Obras
- Obscured
- Obsessed (Book #12 in the Vampire Journals)
- Obsession
- Obsession (Tome n 12 de Mémoires d'un Vampire)
- Occult & Supernatural Tales
- Ocean of Blood
- Odisea del mole
- Odnaleziona (Część 8 Wampirzych Dzienników)
- Odriel's Heirs
- Of A Dark Heart
- Of Bells and Thorns
- Of Breath And Soul
- Of Fur and Ice, a Werestory
- Of Metal and Wishes
- Of Snow and Whiskers, Werestory 2
- Of the Book
- Of the Book
- Of the Trees
- Of Time & Spells
- Off the Deep End
- Ogres at Alcatraz Isle
- Oh No! You Didn't!
- Ojos en las sombras
- Okul Da Vampir Hayatı :Türk
- Oleah Chronicles: Truth
- Olive and the Backstage Ghost
- Olivia Bitter, Spooked-Out Sitter!
- Oltre il bosco
- Olvídate del resto
- Olympia 1. Punteras negras
- Olympia 2. Un paso más
- Ombre
- Ombre che camminano
- Ombre et Damnation
- Ombres
- Omega Awakens
- Omens Bite
- Ominous
- Omvänd (Bok #1 i Vampyrjournalerna)
- ON A DARK CHRISTMAS NIGHT – 25 Holiday Spook Classics & Murder Mysteries
- On a Dark Wing
- On Fire
- On Gallows Hill
- On Ghosts
- On Midnight Beach
- On ne peut plus jamais rentrer chez soi
- On Shadowed Wings
- On the Bay and a Child Found
- Once in a Full Moon
- ONCE UPON A ZOMBIE
- Once... Tales, Myths and Legends of Faerie
- One Dead Girl
- One Night at Begun Kodar Railway station
- One Night in Doom House
- One Truth, No Lie
- Onibi: Diary of a Yokai Ghost Hunter
- Only a Monster
- Only A Phase, Ma: A Gallery of Oddities Story
- Only If You Dare
- Only the Moon Howls
- Only the Stars Know Her Name
- Onwaachige the Dreamer
- Opa's Halloween Handful
- Open Mic Night at Westminster Cemetery
- Ophie's Ghosts
- Opération "Maurice"
- Opętana (Część 12 Wampirzych Dzienników)
- Oracle
- Order
- Origins
- Orión
- Orphan Spirit
- Orrendi per sempre
- Oscar le Médicus - tome 03 - le grimoire qui sait tout
- Oscar le Médicus - tome 1 Le pendentif magique
- Oscar le Médicus - tome 4 L'ordre secret des Médicus
- Oscar le Médicus - tome 5 Les cavaliers du ciel
- Oscar le Médicus - tome 6 : La Vengeance du Prince Noir
- Oscar le Médicus - tome 7 La Salle des Gongs
- Oscar le Médicus, compilation - tomes 1 & 2
- Oscar Pill Les deux royaumes
- Oscure Discendenze
- Oscuri Segreti
- Oscuros (Oscuros 1)
- Ossessionata (Libro #12 in Appunti di un Vampiro)
- Otage de la nuit - Le roman du film Netflix : les pages de l'angoisse - Dès 11 ans
- Othello (Shakespeare For Everyone Else #2)
- Other Words for Smoke
- Otherkin
- Others See Us
- Othersphere
- Otherworlds - Tome 1