Love in the Mask - a Korean manhwa

The Higurashi manga was probably my favorite (Pretty well-known but still. Another one that is sem-well known is Elfen Lied)

Are you Alice?
Dogs: Bullets and Carnage
They're both not as popular as they'd deserve
D.Gray-man as well but it's more popular than the other two

Cowboy Bebop
Samurai Champloo (It's a spiritual successor to CB)
Plantes
Illegal Rare
Vampire Games
Dance in the Vampire Bund series
Tomee 
Ito Junji's Cat Diary (What's funny is the story, plus, he wrote Tomee and other creepy/ scary stuff that's ripe for Halloween)
Zombie Powder (Written by the same guy who wrote Bleach)
Doubt aka Rabbit Doubt
Chibisan Date (Written by the same guy who wrote Axis Powers Hetalia.)

These are but some of the many manga that I would recommend. Sorry, if it's detailed, but I feel that I ought describe them a little.

-Aiki: a series where the MC is a martial arts prodigy and several women want to either become his pupil or defeat him. Along the way he gets into a lot of perverted situations. The thing is, almost no one can beat him up as he is incredibly skilled and doesn't hold back if they're serious about hurting him. This is one of the few manga where the MC isn't a weak willed character who gets into perverted scenarios. He's sadistic, extremely straightforward and would not hesitate to deliver a painful blow against female martial artists.

-Ubel Blatt: a dark fantasy that resembles Berserk. A young man is out of his way to kill seven heroes that messed him and almost killed him in the past. However, the thing is that there is another prophecy stating that these seven need to live to save the world.

- Tripeace: Set in a sci-fi/fantasy world where various skirmishes between kingdoms take place. The MC has amnesia and joins a group known as Tripeace that is bent on ending war. Each soldier of Tripeace follows three personal dogmas to ending war and conflict. One of the dogmas the MC follows is that war can be ended by crossdressing. 

- Franken Fran: A young doctor goes around saving various lives through extremely grotesque and controversial manners. Being saved in a similar manner, she makes it her duty to improve the field of medicine and has dedicated much of her career to saving peoples from death, even if it means that they would have to suffer painfully in life.

- Necromancer: A young man makes deals with various clients, who ask him to resurrect people from the grave. However, not everything is always as it seems, as some of the resurrected turn into frighteningly dark manifestations of their former selves.

- A Bride's Story: A historical manga that looks into the lifestyle of Turkic Central Asia. There isn't too much of a plot, but looking into the relationship between a bride and her very young husband is very heart warming. Also, the creator also made the manga version of Emma.

- Nukoduke: a comedy series about a young man who adopts Nukos, little chibi cat people. Like the earlier, there isn't really a plot, but there is enough adorableness to give you a heart attack.

- T-Rex Kanojo: Again, like Nukoduke, except we look at dinosaur people. 

- Keyman: a very gritty manga that is very reminiscent of western comics like Watchmen. It shows an alternate timeline, where humans and beastmen coexist. At the center of this world is a superhero named Keyman. However, he is one day murdered and it is up to the police department to find out who exactly Keyman was and who his killer(s) are.

- Shinobi No Kuni: Set in the sengoku period of Japan, it takes a look at one shinobi of Iga and his attempts at making money during the period. It's a historical manga, so you can easily look up how things work out. However, what catches the attention is the flow of the story and the characters.

- Nobunaga no Chef: Another historical manga that takes place in the Sengoku period. However, the main character is a chef that traveled from the future. It shows how he manages to win over various hearts through cooking. 

- Hinamatsuri: A yakuza finds an esper girl suddenly in his home. His lifestyle is flipped upside down, as he suddenly takes the responsibility of father to a nearly uncontrollable child who's lazy, often selfish and quite stubborn. 

- Kuro: a short manga, often just one page, of a girl and her monster cat. It's adorable at first, but as the series progresses, you soon discover that there is so much more eerie things at work.

I really enjoyed reading "Arisa". The artist is the same as the one for "Kitchen Princess". I like how it's not a typical shoujo manga, but there's a bit of action and mystery as well.

I also liked "One Thousand and One Nights", a Korean manhwa, but never finished it.

I wish someone would license "Zenmaijikakake no Tina". It's so cute.

limit

i really like survival games theme  , one of them is ousama game  

paradise kiss and blackjack. its a shame IDK a lot of people who know black jack. It was made by osamu tetzuka, father of all manga

-a cruel god reigns
-with the light
-a brides story
-jellyfish princess
-mahou shojo site
-gengaku picasso
-parasyte
-no longer human
-monster musume
just to name a few

Black Bird

I would recommend manga Re-Life, Real account, Koi to uso and there's korean manga called Witch hunter.

Not sure if this was mentioned, though I love Sorcerer Hunters.
It was an amazing series, the anime couldn't do what
Satoru Akahori and Rei Omishi cultivated, though came close.