(contains a max of three book per series, otherwise this would be a long ass list) (also it's probably kind of dated. There has been a lot of releases and I'm too lazy to update the list)

• A Time Odyssey - Arthur C. Clarke
  • 01: Time's Eye
  • 02: Sunstorm
  • 03: Firstborn
• Dirk Gently - Douglas Adams
  • 01: Dirk Gently's Holistic Detective Agency
  • 02: The Long Dark Tea-Time of the Soul
  • 03: The Salmon of Doubt
• Ex-Heroes - Peter Clines
  • 01: Ex-Heroes
  • 02: Ex-Patriots
  • 03: Ex-Communication
• Expanse - James S.A. Corey
  • 01: Leviathan Wakes
  • 02: Caliban's War
  • 03: Abaddon's Gate
• H.I.V.E. - Mark Walden
  • 01: Higher Institute of Villainous Education
  • 02: The Overlord Protocol
  • 03: Escape Velocity
• Hainish Cycle (stand-alones in the same world) - Ursula K. Le Guin
  • 01: Rocannon's World
  • 02: Planet of Exile
  • 03: City of Illusions
  • 05: The Dispossessed
  • 06: The Word for World is Forest
  • 07: Four Ways to Forgiveness
  • 08: The Telling
• John Dies at the End - David Wong
  • 01: John Dies at the End
  • 01.5: John and Dave and the Temple of X'al'naa'thuthuthu
  • 02: This Book Is Full of Spiders
• Jumper - Steven Gould
  • 01: Jumper
  • 02: Reflex
  • 03: Impulse
• Rosemary's Baby - Ira Levin
  • 02: Son of Rosemary
• The Last Survivors - Susan Beth Pfeffer
  • 01: Life As We Knew It
  • 02: The Dead and the Gone
  • 03: This World We Live In
• The Long Earth - Terry Pratchett and Stephen Baxter
  • 01: The Long Earth
  • 02: The Long War
• The Once and Future King - T.H. White
  • 01- 04: The Once and Future King
  • 05: The Book of Merlyn
• The Passage - Justin Cronin
  • 01: The Passage
  • 02: The Twelve
  • 03: The City of Mirrors
• The Pledge - Kimberly Derting
  • 01: The Pledge
  • 02: The Essence
• The Vampire Chronicles - Anne Rice
  • 01: Interview with the Vampire
  • 02: The Vampire Lestat
  • 03: The Queen of the Damned
• Thursday Next - Jasper Fforde
  • 01: The Eyre Affair
  • 02: Lost in a Good Book
  • 03: The Well of Lost Plots