From Kokoro no Oasis:

Tomas is a proud and fearless assassin who has never failed a commission. So what happens when he's commissioned to kill Myra, an immortal vampire?

Mangaupdates:When a vampire is in love with a human...and you add zombies into the mix...

What would you do if a tiger skin bikini-clad alien followed you to school every day? Poor Ataru's life has never returned to normal since volatile extraterrestrial princess Lum fell for him. Now an excruciatingly wealthy and genteel rival, Mendo, adds to Ataru's torment. Not to mention an unending stream of extraordinary classroom visitors and educational materials including incompetent cherry blossom spirits, a legendary nightmare-eating tapir, and a fourth-dimensional camera that breeches alternate realities.

Note: In 1981, this series received the Shogakukan Manga Award.
Won the 18th Seiun Award for Best Comic (1987).

From Storm in Heaven:

What happens when your mother and her best friend decide that their two children will be soul mates?

It seems fate was playing a trick, though, because when the two children meet each other, neither is a girl. Since both of the two children turned out to be boys, nothing will happen, right? Though the mothers might have dropped the idea of marriage, destiny might have other plans: the lives of the two boys may be bound by a red thread.

Has characters from Dear Myself and an early (but different) incarnation of Tsuda from Color.

From Girls' Generation Scanlations:

Kikuchi-sensei rejected a love confession. The boy cursed him, the next day on the train going to his new job, every man in the car wanted him... But why were they harassing him?! If it wasn't for the young Akane, who knows what might have happened?

From Viz:
Rejected way too many times by good-looking (and unattainable) guys, shy Riiko Izawa goes online and signs up for a free trial of a mysterious Nightly Lover "figure." The very next day a cute naked guy is delivered to her door, and he wants to be her boyfriend!
Has Riiko died and gone to heaven? The cute guy turns out to be sweet, smart, a great cook, and lots more. And he looks like a million bucks, which is what he's going to cost Riiko if she doesn't return him in time...

*Includes two other side stories in the last volume called:

• Ohoshisama ni wa Sasemasen! (I Won't Let You Become A Star!) -
A special short story that was published in a freebie book put out in Sho-Comi. Sneaking into a boys' school to exterminate ghosts! However, what is the boy Chima has always admired doing there...!?
- ShoujoMagic

• Shounen Aromatic (Aromatic Boy) -
Kabuki Takitsugu is a boy who has the family trait of smell. He can smell anyone's fragrance and find their perfect match. One day, a mysterious girl named Hatsune appears before him, asking him to find a match for her. But, for some strange reason.. Hatsune doesn't have a scent.

As a woman of a famous ninja clan, Kinuko have a trouble: she has the ability "to see through one's clothes".

Little story about Umi-chan and her hairy friends.

Included in the Katteni Kaizo Offical Fanbook.

The story of castle otaku, Ume, meeting a sexy blonde escort girl named Shigure...Is that really it or is there more? Read and find out!

After Tsubaki Ryuta is run over by an alien, he receives superpowers that he can’t control. How is Ryuta going to make use of his new powers? Being the new hero of town could be an option, but…

Raised in the hope that I would be a boy full of courage and strength, they named me "Yuu."
To be a girl filled with kindness and love; that's how my twin sister, "Ai," was raised.
That's how our parents named us-
But... Our parents' wishes were reversed.
A story about twins who risk everything to protect one another and to find his or her happiness in the switch they call twins game. (Premiered in Waai Mahalo)

From Ivyscan:

In 1875, after the death of her parents, Uno goes to live in the Kanou household as a companion to Mariko, who is the same age as Uno. The two girls become very close and attend Cimons private school.
This great romance tells the story of the loves and dreams of two girls growing up during the westernization of Japan in the Meiji era.

Yuuki Narusawa, a college student looking for a tutoring job runs into Ryou Misaki, who is in search of a tutor who looks good in a maid uniform.

From ShoujoMagic: This manga is loosely based on The Tale of Genji / ??????(Genji Monogatari) and is a MUST read! When the Emperor takes a new Empress, she is barely older than the Emperor's son Hikaru. She becomes both the one woman Hikaru loves and the one woman he can never have. And so Hikaru's feelings roam as his body wanders from bed to bed, seeking a replacement for her. When he finds the girl he believes can take her place...he commits a terrible sin. Now, a thousand years later, Hikaru's nightmares become reality as he is punished for past deeds in a new life--the greatest playboy in all of history...shakes like a lamb when any girl touches him!

A collection of stories:

1. The Boundary Between Archer and Scorpion
2. The Long, Far Road
3. Giraffes' Necks Are Too Long
4. The Imaginary Land
5. Flowers Forming a Parabola
6. Her Cat Wards Off My Bad Dream
7. Itoshii no Maid-sama (Miss Beloved Maid)
8. Capturing You
9. The Crow Woman
10. A Love Song in a Nameless Country
11. The Prince of the Night Sky and the Princess of the Morning Glow

Ganota Utsuki leads a normal life, working for a big company in Tokyo. She has just one big secret: she's a giant Gundam otaku and she doesn't want anybody to know! And the fact that her number one love interest despises all things Gundam doesn't help any either.

While many of us would probably scream at even the thought of a ghost being near us, Freshman Nimura Kensuke just thinks of it as a common everyday thing, seeing as how he has the uncanny ability to see so many of them on a daily basis. Things soon heat up for him when he meets a girl who changes his life from then on. Her name’s Kagura, and she has the power to summon a mighty “spirit devourer”--otherwise known as a “Ga-rei”--called Byakuei. So, what’s Nimura to do? Chase down the evil spirits and have Kagura summon the Ga-rei to devour them, of course! Now, come feast on their adventures like some ravenous Ga-rei!

It's about a girl named Hatsune with a "bad mouth", for lack of a better description. She's kind-hearted, but her mouth spews the total opposite of what she means (which is probably due to the fact that she grew up with only male influence). And so she is seen as an arrogant, vulgar girl at her school, but all she wants is a boyfriend. Well, that is, until she gets accepted at the Maidens' Club, where she meets a guy named Kirie, with a somewhat unique habit that happens when a girl comes within a foot of him. And everyone says he's gay, even Hatsune. How will these two fare? Will Hatsune have a boyfriend at last? Will he be more than just a friend?

4-koma about a "human" girl attending what turns out to be a school for monsters.

Really cute and funny!