Nobody brought up the real ones? Quite disappointed^^

Definitely Fraternite
Minikui Mojika no Ko
MinDeaD BlooD ~支配者の為の狂死曲~
ダストマニア・グロテスク ~解体挿入新書~ is even english translated.
But most stuff which got translated into english is pretty harmless the real stuff is almost never translated i ony know one or two exceptions.

There is so much more out there however if you cant into japanese you wont find much.
You also could try out Maggot Bait and Cartagra ( prequel for kara no shoujo)
Else you can always serach for certain tags.