The Cursed Chateau by James Maliszewski
This is an adventure originally designed for Lamentations of the Flame Princess and revolves around a haunted house where as the leader draws from a deck of cards to generate random events. There are plenty of uses and outcomes - mad scientists, haunting, sorcerers, maybe even a ruse to confuse guests, or some entity causing them all to go mad. I personally am going to swap this for Loch Varn in my scenario instead of using the Magientist facility.
Blackwater Creek by Scott Dorward
A scenario for 7th edition Call of Cthulhu where a town is being slowly taken over by parasitic worms after unearthing a cave in the ground. Fits easily into Esteren's Gray Bogs. The idea that some ancient beast lurks beneath the earth and has been disturbed, something never seen, but the party has to deal with nevertheless is the pinnacle of horror and mystery. Combine that with the danger of an infectious disease, flesh-eating worms, and zombiefied townsfolk due to the parasites being in the water supply and you have a perfect storm.
Missed Dues by Mike Mason
Another scenario from 7th edition Call of Cthulhu. This is a creepy criminal investigative horror where a thief steals something he doesn't quite understand and it drives him mad. Lots of opportunity for getting involved in the criminal underbelly of a town, and dealing with corrupt religious figureheads (a town figuring out their Demorthen is actually a Morcail for example, or a fake church of the Temple swindling people). Lots of opportunity for stressing the sleuth side of things.
Thieftaker by D.B Jackson
A novel in which the main character is a thieftaker, or bounty hunter, and also secretly a user of magic in a time when that could get him hanged (colonial america). He is employed to find out who killed a young girl, because someone suspects it might have been with magic. It is a lovely tail of misdirection, getting in too deep, and uncovering a bigger plot. A must read!
The Lies of Locke Lamora by Scott Lynch
While a fantasy novel, I have drawn huge inspiration from the plot of this book. It deals with gangs, politics, and heists, with a little witchcraft thrown in. The plot is impeccable, and can be a good source for a scenario. The leader of a band of religious thieves (worshiping a hidden god of theft) but still in the employ of a gang leader underneath the government is confronted with a strange new employer that coerces him into helping. Lots of betrayal, swindling, epic twists, and enough content to build a scenario from. I don't want to spoil the plot, its so good!
The Wicker Man SPOILERS
A 1973 British mystery horror film directed by Robin Hardy. It is based on a novel called Ritual by David Pinner. The main character is summoned to a remote island under the guise of helping to find a missing girl. The cult on the island has the intention to dupe him and make him unknowingly fulfill certain "prophecies" in order to sacrifice him to their pagan celtic god.
Boneyard by Seanan McGuire
A novel based on the tabletop RPG Deadlands, set in the weird west. I'll let the description explain how good this book is for me. With a little tweaking, this can be great Esteren material.
---Annie Pearl is the keeper of oddities, the mistress of monsters. Her unique collection of creatures is one of the circus’s star attractions, drawing wide-eyed crowds at every small [...] town they visit...
Hoping to fill its coffers before winter sets in, the circus steers its wagons to The Clearing, a remote community deep in the [...] wilderness, surrounded by an ominous dark wood. Word is that a traveling show can turn a tidy profit at The Clearing, but there are whispers, too, of unexplained disappearances that afflict one out of every four shows that pass through the town.
I'll continue to update the more things I find that fit the theme of Esteren. If anyone has any contributions, please add them.