Not a DM / etc but our DM had us all fill in a horror questionnaire to gauge what can and cannot be included in campaigns. We never did run a horror TTRPG (yet) but it was a nice thought.

I want to bring up “Silent Legions”. It’s an OSR horror game by Kevin Crawford. Softcover is $25 on drive thru rpg. It has tools for setting up Antagonists and world creation. Its simpler to run than Call of Cthulhu and cheaper than Delta Green. Great system and uses the same OSR style system as any of his other stuff so is real easy to learn and run.

Choose a genre of horror first. Choose a system that emulates it well. Choose an intensity. Is horror the main focus, or do you just want a splash of it here and there? Make sure everyone is on board obviously. Resarch works from the specific genre. A psychological horror is gonna play out differently than a slasher movie inspired session.

My favourite tip take your time. Start with the boring life. The danger about online dating is to meet a walking soviet-parade of red-flags, not to meet a vampire who want to suck your blood. Spending a night camping in the wood is pretty fun, what you really fear is to be snitched on and get fined for “illegal camping” and an unplanned thunderstorm can definitely turn a fun evening into a bad experience, nobody really fears the witch from the woods, it’s a talefor kids isn’t it ?

Then once you took the time to play some “normal” elements, slowly put some uncany elements, a_ctually while you’ve feel like you spoke for hours with your date your watch tells you only 5 minutes passed, and your coktails are still full_. The night camping was pretty fun, but why is the forest so silent in the morning.

This help ensuring that there is a strong link between Player and character, and avoid falling in the comedy horror where fighting Zombie with blood up to knee is the new normal (Note that comedic horror is a genre by itself, and can be pretty fun to play too, but it’s different than real horror)

If you want to use dnd 5e sandy Peterson did a couple adventures and a base ruleset called Cuthulhu Mythos. Theyre a lot of fun and totally built around suspense. Page 70 starts the chapter where they review insanity and dread. I love the dread mechanic.