A series of science fiction books by Dennis E Taylor.

A series of Christian Fiction books featuring Wolfe Boone.

A fantasy series by Mark Lawrence.

A series of novels by Gene Wolfe that takes place after Book of the New Sun.

Book of the New Sun is a science fiction series by Gene Wolfe.

A series of novels by Gene Wolfe that takes place after Book of the Long Sun.

A series by N K Jemisin

A series of novels based on the television series Buffy the Vampire Slayer.  This series is aimed more toward the young adult audience.

A series of novels based on the television series Buffy the Vampire Slayer.  This series is aimed toward the adult audience.

A series of supernatural fantasy from the Author Amber Benson, also known from Buffy The Vampire Slayer.

Set in the Star Wars universe set 12 ABY.  This is an unofficial series comprising three related stand-alone Star Wars novels.

A series of books about a land that time forgot.

A part of the Harry Bosch world by Michael Connelly.

A series of modern fantasy books targeted to teen and young adults by Kami Garcia and Margaret Stohl.

A series of graphic novels reprinting the Cerebus comic books written by David Sim and illustated by Dave Sim and Gerard.  All issues are reprinted except for 51, 112, 113, 137 and 138 which were reprinted in Cerebus Number Zero..

A trilogy of books by Lois McMaster Bujold that began the World of the Five Gods.

A series of western written by Louis L'Amour.

A series of books written by C J Cherryh that takes place in the Alliance-Union Universe.

Series of fantasy novels by Raymond E Feist.  A subset of the Riftwar Cycle.

The Childe Cycle is an unfinished science fiction series by Gordon R Dickson.

A series within the Deryni world.

A series of science fiction novels by Adrian Tchaikovsky.

A series of children's books by the creator of Jame Bond - Ian Fleming

The full Amber series by Roger Zelazney.

A series of fantasy novels by Lin Carter.

A series of fantasy novels for younger readers by Lloyd Alexander.

A series within the Deryni world.

A series of science fiction novels by John Connolly and Jennifer Ridyard.

The overall span of Thomas Covenant novels in order.

The first trilogy by Stephen R Donaldson with Thomas Covenant as the main character and introducing The Land.

A series by Jim Butcher.

A duology written by Kevin J Anderson and Neil Peart from the rock band Rush.

A series of sci-fi novels written by Piers Anthony.

A series of novels by Jim Butcher.  To my understanding - supposedly these books sprang from a debate over what was better in a story, great character development or a unique story idea.  Jim Butcher asked for two known story ideas and he said he would make an interesting story out of them using character development.

A series of science fiction omnibus works containing two novels each by A Bertrand Chandler.

A short run series published by Target Books featuring solo adventures of people who were once companions of the Doctor in Doctor Who.

A science fiction series by C J Cherryh.

A series of books about Conan the Cimmerian written by Robert E Howard, L Sprague de Camp and Lin Carter.  This is the core series of books which are all from or based on stories or notes by Robert E Howard.

The seven book Conan series written by Robert Jordan.

Series of fantasy novels by Raymond E Feist.  A subset of the Riftwar Cycle.

Star Wars universe series set 18 ABY.

A Crime Mystery series written by J K Rowling under the pseudonym Robert Galbraith.

ACOTAR - A fantasy series by Sarah J Maas