- Coolhunting
- Coop
- Cooper
- Cooper Alley Ghost
- Cop (Star Minds Lone Wolves)
- Coplete Terro-Human Future History Series of H. Beam Piper
- Copper Centurion
- Copper Cove
- Copy
- Copy Cat
- Coração Atómico
- Coração de Corda
- Corde à vide
- Core Charge
- Core of Confliction
- CORE REALITY
- Core Threat: Mission 11
- CoreFires: From Death Star Designer Colin Cantwell
- Cormorant Run
- Cornucopia
- Corona
- Corporate Pain
- Corpse Run
- Corpus Delicti
- Corpus Delicti: erweiterte Ausgabe
- Correspondence
- Corroded
- Corrupted Food Storage
- Corruptor
- Corsa nello spazio
- Corsica's Revenge
- Corvus
- Cory's Fears
- Cosm
- Cosmic Apocalyptic Phenomena:
- Cosmic Castaway
- Cosmic Corsairs
- Cosmic Crust
- Cosmic Cyclone: The Silent Planet - A Space Opera
- Cosmic Echelon
- Cosmic Encounter
- Cosmic Engineers
- Cosmic Fusion
- Cosmic Howling
- Cosmic Justice
- Cosmic Knights
- Cosmic Lock
- Cosmic Love : Science Fiction Romance Collection
- Cosmic Mate
- Cosmic Mates : Alien Menage Romance Collection
- Cosmic Powers
- Cosmic Rift
- Cosmic Rift I - Riftworld GT-4416 - The Unveiling
- Cosmic Shag (Episode Four of Farther Than We Dreamed)
- Cosmic Sutra
- Cosmic Trifecta : Alien Menage Romance
- Cosmic Trilogy
- Cosmic Wars
- Cosmically Yours - Sci fi Alien Romance
- Cosmiton
- Cosmo
- Cosmocopia
- Cosmogramma
- Cosmophobia
- Cosmos
- Cosmos Incorporated
- Cosmos Quest
- Cosmovorous
- Cost of the Hunt
- Cotton Crossing
- Cougar's Roar
- Couleur Lila
- Council’S Twelve
- Count to a Trillion
- Count to Infinity
- Count Zero
- Countdown Armageddon
- Countdown City
- Countdown zum Untergang
- Countdown: H Hour
- Countdown: M Day
- Countdown: The Liberators
- Counter Spike
- Counter Strike
- Counterattack
- Counterattack: The Guild War, Book 2
- Counterfeit Conspiracy
- Counterfeit Stars: Agents of ISIS, Book 8
- Countermind
- Counterstrike: The Last World War, Book 2
- Counting Heads
- Countless as the Stars
- County Fairy Tale: A Beauregard the Monster Hunter Short Story
- Coup D’état
- Courage in the Ashes
- Court of Nightfall
- Courage in the Ashes
- Court of Nightfall
- Court of the Grandchildren
- Court-Martial on the Charys
- Courting Trouble
- Cousin Entropy
- Coven Enforcers Bundle
- Covenant
- Coventry
- Cover Fire
- Covert Defense Force: Sake of Time
- Covert Game
- COVERT MESSAGES
- Covert Webs
- Coverup
- Covid – Opération plaquette
- Cow Fart Apocalypse
- Cow-Boy
- Cowboy Feng's Space Bar and Grille
- Cowboys and Indians
- Cowl
- Coyote Learns a Lesson
- Coyote's Mate
- Cozened: A Cybil Lewis SF Mystery
- Coûte que coûte
- Crache
- Cracked
- Cracked Control
- Cracked Open
- Cracks in the Pillars
- Cradle and Grave
- Cradle of Chaos
- Cradle of Kings
- Cradle of the Future
- Cradle of the Sun
- Craggy's Final Last Flight
- Craggy, A Flight Too Far
- Crap Shoot
- Crash
- Crash - A Dark Post-Apocalyptic Tale
- Crash Dive
- Crash II - Highrise Hell
- Crash III - There's No Place Like Home
- Crash IV - Run Free
- Crash V
- Crash Wagon: Book One - Family Ties
- Crash Wagon: Book Three - Enemies and Allies