Incredible story about, well, friendship for the most part. Relatable characters and immense amount of detail means there's probably going to be a character you can self-insert to or entirely empathize with as if they were actually real. Mostly not that difficult to follow story with a lot of twists and turns, and you're encouraged to theorycraft throughout the story to find out what happened next and have your expectations blown away by the next chapter. So far I've read
Main series (Onikakushi - Matsuribayashi)
Epilogue (Saikoroshi)
Some side stories (Taraiwamashi, Tsukiotoshi, Yoigoshi)
Left to read:
Onisarashi (manga exclusive)
Someutsushi, Kageboushi, Tokihogushi, Fragments, Miotsukushi PS2 and Ura
Batsukoishi (sus chapter)
Hirukowashi (daybreak chapter)
Hinamizawa Bus Stop (proto higu)
Higurashi Outbreak (zombies??)
Kamikashimashi (outbreak continuation)
a bunch of other shit why is there so much higurashi