The Dunwich Cycle: Where the Old Gods Wait

The Cthulhu Cycle: Thirteen Tentacles of Terror (Call of Cthulhu Fiction)

The Nyarlathotep Cycle: Stories about the God of a Thousand Forms (Chaosium fiction)

The Disciples of Cthulhu (Call of Cthulhu Novel)

The Book of Eibon: Histories of the Elder Magi, Episodes of Eibon of Mhu Thulan, the Papyrus of the Dark Wisdom, Psalms of the Silent, and the Eibonic Rituals