4 out of 6 idea for Cthork Borg supplment are from Pulp Media, or Media inspired by Pulp.
Age of Mythic Twilight is clearly inspired by the Hyborian Age of Robert E. Howard, mix with some Lord of the Ring, and various mythology about ancient civilization.
Wild and Wylder Thing is from Renowed Explorer and Curious Expedition, which are very Pulp inspired, the latter more weird, while the former more action packed. And also Tarzan.
Forgotten Age Beneath the Modern Land is inspired by Theosophy mainly, as it very much shape the early 20th century Pulp story, with it ancient civilization, secret masters, and the most famous Hollow Earth Theory, and other Pulp story about Hollow Earth.
Stranded on the Red is the next and final idea I have for Cthork Borg, and it's inspired by John Carter of Mar series, and will be mainly focus on the mar civilization, and also a lot of weird science stuff.