- U-Turn - Irgendwann kommt jeder an
- U.N.E. - Funke der Rebellion
- U.S.S.
- U.S.S. Humanity
- Ubermensch
- Uchronic Tales
- Uchronic Tales: The Zeppelin
- Uchronie pour guerriers de l'ombre
- Ucronia
- Uderzenie #2 Wojny Palladowe
- UfO
- Ufo case
- Ufo Crash - L'ultimo Natale sulla Terra ep. #4 di 10
- UFO Vantassels in Space
- Ugly
- Ugly Earthling
- Ugly Thirteen
- Uksak Science Fiction Fantasy Großband 6/2019
- Uksak Science Fiction Fantasy Großband 7/2019
- Uksak Science Fiction Fantasy Großband 9/2019 - Ferne Welten, ferne Galaxien
- Ull
- Uller Uprising
- Ullr Uprising
- Ultima genesi (Urania)
- Ultima Thule
- Ultimate Mid-life Crisis
- Ultimate Science Fiction, Fantasy, & Horror Collection #1
- Ultimate Temptations
- Ultimatum
- Ultra Spectrum
- Ultragoth
- Ultramundo (Edición especial)
- Ultraviolet
- Uluru Rising
- Um mundo de Felicidade
- Uma Forja de Valentia (Reis e Feiticeiros – Livro 4)
- Uma praga a mais, uma erva daninha a menos
- Un anno nella città lineare
- Un billet de loterie – suivi d'annexes
- Un capitaine de quinze ans
- Un capitaine de quinze ans – suivi d'annexes
- Un diálogo a la velocidad de la luz
- Un drame au Mexique – suivi d'annexes
- Un drame dans les airs – suivi d'annexes
- Un drame en Livonie – suivi d'annexes
- Un Giro En El Tiempo
- Un habitant de la planète Mars [édition intégrale revue et mise à jour]
- Un habitant de la planète Mars [édition intégrale revue et mise à jour]
- Un hivernage dans les glaces – suivi d'annexes
- Un homme d'ombres
- Un Monde de Bonheur
- Un monde à l'éternité
- Un mondo ostile
- Un palazzo tra le stelle
- Un pas en avant (Pas de paradis sans... l'enfer, vol. 3)
- Un român în lună
- Un sonido atronador
- Teixcalaan (Tome 1) - Un souvenir nommé empire
- Un tempo altrove
- Un tour en Arkadie
- Un tuffo nel relitto
- Un viaggio senza confini
- Un viaje sin confines
- Un Voyage sans entraves
- Un weekend del 4° tipo
- Una historia de los tiempos venideros
- Una leyenda del futuro
- Una manciata di luce
- Una princesa de Marte
- Una splendida giornata
- Una vita da... ovvero: le procellarie di Andrea
- Una's World
- Unafraid
- Unaltered
- Unbeaten
- Unbeknownst II: Time Travel to Mid-Nineteen Century Oregon
- Unbelief Trilogy
- Unbelievable: A Novel of the Exotica Chronicles
- Unbounded
- Unbounded Series Books 1-3
- Unbroken
- Unbroken Fire
- Uncanny Tales of Crush and Pound 17
- UNCGSC: The Facility
- Unchained
- Uncharted Frontier EZine Issue 15
- Uncharted Stars
- Uncharted Territory
- Uncharted: Book Seven of The Channel Riders
- Uncharted: The Fourth Labyrinth
- Unchosen Destiny
- Uncivil Service
- Uncle Edgar - United Space Force
- Unclear Skies
- Uncommon
- Uncommon Life
- Uncompromising Honor
- Unconquerable Sun
- Uncontainable
- Undead at Groom Lake
- Undead Genesis: Zombie
- Undead Island (Escape - Vol. 3)
- Undead Island (High Tide - Vol. 1)
- Undead Island: The Complete Collection
- Undead Reckoning
- Undead Worlds 2
- Undead Worlds 3
- Under a Cloven Moon: The Satanta Run
- Under a Veil of Gods
- Under Arctic Ice
- Under Different Stars
- Under New Leadership
- Under Plum Lake
- Under Roswell
- Under Shadows
- Under Siege
- Under Strange Suns
- Under the Dark
- Under the Flickering Light
- Under the Green Star
- Under the Heel of the Aether Imperium
- Under The Knife
- Under the Radar: A Tale of Super City
- Under the Radar: The Blake Hemlock Chronicles
- Under the Skin
- Under the Sun
- Under Two Moons: Paradisi Chronicles
- UNDERBREAK
- Undercity
- Underdogs
- Underestimation
- Underground
- Underground Man
- Underground: The Day of the Sun
- Underscore_
- UnderSilver
- Undertow
- Underwater World
- Undisclosed (Undisclosed Trilogy, Book 1)