The following relics and artifacts were discovered by the investigators as they delved ever deeper into the mysteries surrounding The King in Yellow.

• Bone Whistles, the cult devices used by the followers of Hastur to call down the Byakhee.
• The Yellow Sign, an occult symbol connected to The King in Yellow and Hastur. This image seems to have a disturbing effect on those who see it.
• The Chime of Tezchaptl, a silver bell which could be imbued with the power to reflect magic. Discovered in Lawrence Bacon's home, the process for enchanting the chime was found in The Turner Codex.
• Springer Mound Monoliths, nine granite obelisks initially discovered at Springer Mound and then again later at Loch Mullardoch.