Cubicle 7 subsequently published a number of supplements:
- Black Bag Jobs, a compilation of scenarios
- The Agent's Handbook which develops the agents' characters and the internal procedures of the organization
- The Mythos Dossiers, a compilation of in-game documents to use as play-aids and scenario seeds
- License To Summon, which give more details on the various forms of sorcery in the game universe
- God Game Black, which provides more information on the Sleeper's Plateau and how to introduce an eschaton menace in the game
- Cultists Under The Bed gives more information on the working of various forms of sects and cultists, with several examples of organizations
- Unconventional Diplomacy, a compilation of scenarios
- Targets Of Acquisition, which provides dossiers of several occult artefacts
- As Above, So Below, introduces rules for using special forces in the game and adding a political dimension to games. It also includes two new scenarios.
A GM screen was announced but was never released. Cubicle 7's licensing agreement with Chaosium expired by mutual agreement at the end of 2017. In 2019 Cubicle 7 stated that the licensing issue would need to be resolved, or a new system introduced, before a revised edition could be published.
- Shannon Appelcline (2011). Designers & Dragons. Mongoose Publishing. ISBN 978-1-907702-58-7.
- Stross, Charlie (10 March 2010). "For sale; first edition of the Necronomicon (used once)". Charlie's Diary. Retrieved 22 June 2010.
- "Laundry Supplements list on Cubicle 7 website". Retrieved 11 March 2015.
- "Call of Cthulhu and Cubicle 7".
- "Geek Native discuss Cubicle 7".