This is probably the scariest minecraft horror modpack you'll play. Focus on building tension, rather than just throwing a monster in your face and making lots of loud sounds. Only about 30 mods. Also plenty of enviroment and QOL mods.
Will not be listing the included horror mods here so you won't get spoiled- try the modpack out for yourself, or look at the mod list if you really want to know.
Enviroment mods include:
Cold Sweat
Ambient Sounds 6
Biome Music
Dynamic Lights
(And more)
QOL/ Performance mods include:
ModernFix
Just Zoom
JEI
Ferrite Core
Entity Culling
Dynamic FPS
(And more)
Structure mods include:
Valhesia Structures
Additional Structures
No shaders for performances sake. but you're free to add some if your computer can handle it.
Have fun! And pro tip: bring a friend.