Akira: one of the earliest gory animes, it's a classic
Ayakashi: Samurai Horror Tales: Old traditional horror tales of Japan made into animation.
Berserk: man who was born out of a corpse become a mercenary when he becomes older, meets up with a group, becomes friends. Then the leader of group goes crazy, makes deals with demons and kills group but said man survives and vows revenge.
Blood +: A vampire girl who is on a quest to kill her twin sister. On her journey she looses many friends but makes friends as well. Fighting scenes with katana's heart
Blood C: different take on Blood +
Casshern Sins: an android who has amnesia but seems to be the cause of the the earth dying and his traveling companions
Corpse Party: A group of friends about to graduate play a game that is said to keep them together even when they go their separate ways. But instead they are taken to another reality where the dead remain and hunt those that are still alive.
Dance in the Vampire Bund: there are werewolves and shapshifting vamps. The leader looks no older than 10 but she is very powerful and cunning. Fight scenes and blood but has a little humor.
Dansai Bunri no Crime Edge: About a boy whose ancestor was a killer and he inherited said killers powers and weapon and a girl whose hair keeps on growing and is almost impossible to cut. Together they fight enemies who want to kill the girl with their own killer goods.
Gantz: A strange machine brings people back to life so that said people can kill aliens who have come to earth. Be warned, these aliens won't go down without taking a limb or two.
Hellsing (g)
Highschool Of The Dead
Jigoku Shoujo Ai: A girl named Ai is tasked with forcibly taking people into hell by the request of other humans. How do they request, since it is modern day, of course it is through the internet.
Jormungand: about a group of weapons dealer and the relationship between the youngest, a child soldier, and their female leader, who has a few screws loose and loosing more.
Mnemosyne: Immortal humans fighting those who would do any horrific thing to obtain immortality as well.
Noein: sci-fi and alternate realities. Sort of liked it, sort of did not. confused
Penguindrum: Future, aliens, dystopia, family. Depends on person, I did not watch much of it.
Higurashi ga naku koro ni
Umineko ga naku koro ni
Puella Magi Madoka Magica: Magical girls who fight witches but realize the horrible reality of said witches.
Pumpkin Scissors: a military group tasked with eradicating corruption in a cease war era. Liked the manga better.
Pupa (g)
Seikon no Qwaser
Shangri La: in the future global warming has warped the geography of the world. In Japan, an adventurous girl lives within a dangerously dense forest with her village, each individual waiting for the day they are allowed to live in the utopian like building of Japan. Yet there is intrigue within those walls which somehow are connected with said girl. Has fantasy and sci-fi-ish.
Shinsekai yori : about a group of friends who live in a small community of telekinetic users, in an almost utopia like setting. But as these friends grow older they begin to learn of the horror through which and why said utopia was achieved and kept.
Towa no Quon: a group of power users who hide from a governmental society intent on eradicating them as well as those who have awakened to similar powers.
Un-Go : set in the future in a war recovering from war. a private detective and his follower/boss who solve crimes through deduction and with one question a suspect has to answer truthfully.