They Came from the Terrifying West
They Came from Beyond the Grave!, and the Storypath system in general, has been a refreshing approach to a horror system that isn't CoC but also isn't geared toward single-session one-offs (as great as those are!). Currently running it in the 1870's, following a band of people slowly dealing with the demonic infestation that seems to cling to the early transcontinental line. The campaign has been great, the setting itself atmospheric, as I largely run through the They Came From... bestiary.
A perfectly fine excuse to research the actual history surrounding the railway and watch some good horror flicks (definitely looking for suggestions here).
So far, the campaign has been pretty tamed. The party started out in Sacramento meeting a contact who dies promptly and catapults the players to investigate several mysteries: demonic possession, cursed woods, and -- heading into the next session -- cult activities in and around Truckee, which notably has significant real world history to definitely consider thoughtfully.