Just a reminder that the Demon Cults & Secret Societies Kickstarter from Kobold Press ends in a few days. This book will be for Pathfinder and 5th Edition. I've previous discussed the Kickstarter here. The project has unlocked several stretch goals.
I think this would also be a good place to mentioned Operational Unfathomable. Jason of The Dungeon Dozen and the Hydra Collective are putting together this gonzo underworld adventure and setting. A few stretch goals have been unlocked and the Odious Uplands, the realms above the underworld. The book has been written for Swords & Wizardry, but that means it'll be easier to convert to other versions of D&D. One of the stretch goals will be a DCC conversion, which sounds amazing to me. Check out the Kickstarter video for this and tell me that it doesn't sound awesome.