- Clarkesworld: Year Three (Clarkesworld Anthology, #3)
- Clash of Powers: The Colonist
- Clash of the Fae
- Class is In Session
- Class One Act
- Class Reunion
- Classic Cyborg
- Classic Martian Stories, Vol. 1
- Classic Martian Stories, Vol. 2
- Classic Martian Stories, Vol. 3
- Classic Martian Stories, Vol. 5
- Classic Martian Stories, Vol. 6
- Classic Martian Stories: The Complete Series
- Classic Moon Stories, Vol. 1
- Classic Moon Stories, Vol. 2
- Classic Moon Stories, Vol. 3
- Classic Moon Stories: The Complete Series
- Classic Science Fiction Stories
- Classic Venus Stories, Vol. 1
- Classic Venus Stories, Vol. 2
- Classics fantasy – 10
- Classics fantasy – 11
- Classics fantasy – 12
- Classics fantasy – 3
- Classics fantasy – 4
- Classics fantasy – 5
- Classics fantasy – 6
- Classics fantasy – 7. Stories-2
- Classics fantasy – 8
- Classics fantasy – 9
- Classics of a fantasy
- Claude and the Henry Moores
- Claudius Bombarnac – suivi d'annexes
- Clause 57
- Claws of Darkness
- Claws of Death: An Agents of The Emperor Science Fiction Short Story
- Clean
- Clean Install
- Clean Slate Complex (a daynight story)
- Clear Shining After Rain
- Clear Signals
- Clearinghouse
- Cleon Moon
- Cleopatra 7.2
- Clidepp Requital
- Cliente abituale
- Clifford Simak SF Gateway Omnibus
- Climate fiction
- Climate Spirit
- Clive Cussler's The Devil's Sea
- Clive Cussler's The Serpent's Eye
- Cloak And Dagger
- Cloaked Enemies
- Cloaks
- Clockwork Canada
- Clockwork Chaos
- Clockwork Imperium Stories 1-3
- Clockwork Phoenix 5
- Clones
- Clones from the Future
- CLONES: The Anthology
- Cloning Freedom
- Close Encounters of the Old West
- Close Encounters of the Weird Kind
- Close Encounters With the Deity
- Close Encounters: A Gender-Swapping Scifi Space Odyssey
- Close to Critical
- Closeburn Crossing (Altinor Book 1)
- Closer Than You Think
- Closer to Home
- Closet Love
- Closing Time And Other Threshold Stories
- CLOUD 9
- Cloud Dust
- Cloud Field
- Cloud Invasion
- Cloud Rebel
- Cloud Riders 2
- Cloud Riders 3
- Cloud Whale
- Cloudbreak
- Clouds of Darkness
- Clouds of Endyr: The Coral Saga Book Three
- Clouds of Thunder
- Clouds of Venus
- Clouds over Planet X
- Clovis Dardentor – suivi d'annexes
- Clowns Vs Zombies
- Club 27
- Clump
- Coalescent
- Coalition Reckoning
- Coastal Event Memories Volume I
- Cobalt
- Cobra
- Cobra Outlaw
- Cobra Slave
- Coby's Treasure
- Cock-a-doodle Die
- Cocoon
- Cocoon Master
- Code EMP
- Code Headhunter
- Code Ninjas Xtreme and The Dark Prison
- Code Of Law
- Code Red
- Code Teal
- Code Word Access
- Code Word Azurelight
- Code X Discovery
- Codename Omega: Omega Rising
- Codename Salamander
- Codice Hercules (Urania)
- Codice morto
- Coerced Assassin
- Cof
- Coffee Please
- Coffee: 14 Caffeinated Tales of the Fantastic
- Cognizance
- Cohesion Lost
- Coiled Vengeance
- Coins Not Accepted
- Coiper Belt
- Cokie Goes Treasure Hunting
- Cold As Ice
- Cold Beach