30 books in series

Witch World

Witch World is a 30-book series with 30 released primary works first released in 1963 with contributions by Andre Norton, A.C. Crispin, C. J. Cherryh, Elizabeth H. Boyer, Meredith Ann Pierce, Judith Tarr, Pauline Griffin, Patricia Matthews, Sasha Miller, Lyn McConchie, Mary H. Schaub, and Mercedes Lackey.

Witch World
Web of the Witch World
Three Against the Witch World
Year of the Unicorn
Warlock of the Witch World
Sorceress of the Witch World
The Crystal Gryphon
Spell of the Witch World
The Jargoon Pard
Trey of Swords
Zarsthor's Bane
Gryphon in Glory
Horn Crown
Ware Hawk
Gryphon's Eyrie
The Gate of the Cat
Tales of the Witch World 2
Were-Wrath
Four from the Witch World
Storms of Victory
Songsmith
On Wings of Magic
The Key of the Keplian
The Magestone
The Warding of Witch World
Ciara's Song
The Duke's Ballad
Cover 8

Secrets of the Witch World

Witch World: Estcarp Cycle: Trey of Swords, Ware Hawk, and The Gate of the Cat
The Secrets of the Witch
Swords & Spells
The Gates to Witch World
Werehunter
Chronicles of the Witch World