From Tokyopop:
Mayu, the daughter of a café owner, is unlucky in love until she meets “Puchou,” the magical fairy of beverages. Now, whenever Mayu drinks something, she transforms accordingly! Milk makes her grow large, water makes her invisible, pork soup turns her into a cute little piglet. But what will help her win the man of her dreams?

From Tokyopop:
A smoke-filled alley in Chinatown harbors Count D's Pet Shop. The pets sold here aren't your everyday variety and the Count prides himself on selling Love and Dreams in the form of magical creatures that come with an exclusive contract. But buyers beware. If the contract is broken the Count cannot be held accountable for whatever may happen. A fascinating and macabre look into the very soul of human nature.

The Continent of Song is in chaos. The sinister secret society known as Demon Card is using the power of Dark Bring to destroy everything in their path.

The only things capable of stopping Dark Bring are the Rave stones. Unfortunately, the Rave Stones were scattered around the globe in an explosion 50 years ago, so now they must be collected by the Rave Master in order to stop Dark Bring once and for all.

This new task has been given to Haru Glory, a sixteen year old boy from Garage Island.

The World's fate now rests on the new, young Rave Master.

From TokyoPop:

After 1000 years of peace, the wolf god Fenris Fenrir has been reborn. She seeks to find the reincarnation of Balder, the most beloved God, as the land of Midgard sinks further into anarchy. They are both key players in the coming of Ragnarok, the time when fate and free-will shall come into conflict as the very nature of the universe is forever redefined.

RilleL:
Based on norse mythology, ragnarök is the term for the end of the world. Christian equivalence would be the last judgement.

The popular Korean MMORPG "Ragnarok Online" was based on this book.

[From Aku-Tenshi]:

In the center on a metropolis city lies a small, shaky-looking house. A normal... Okay... Not so normal high school student, Sakura Tetsu (and his family), who works day and night relentlessly to support his family's living expenses, lives there. All is normal until one day, people from the future, alien pirates from outer space, appear. The underground kingdom claims Tetsu's land. Will he prevail in protecting his own land? Or will he surrender his land into many more invaders to come? Yes... Weirdness and insanity ensues!

From Yen Press:

Millennium Academy is a school where elite vampires are trained to maintain balance in a world where humans and vampires, who possess far greater physical strength than their human counterparts, coexist. And commuting to this school is Aldred, the most distinctly un-vampire-like vampire to be found in the entire institution. But when Al encounters Kei, a human transfer student to the school, their destinies become intertwined, and the fate of their world as they know it comes to lie in their hands!

Classic short stories from Takahashi Rumiko. Many are comedies.

Volume 1:
"Fire Tripper" (fantasy, romance)
A gas explosion sends high school girl Suzuko and toddler Shuu 500 years into the past. But she lost Shuu on the way, and as a result, Shuu ended up in the past 10 years before her, and is 15 years old when Suzuko arrives.
"Maris the Chojo" (comedy, sci-fi)
A destructive alien policewoman sees a kidnapped quadrillionaire as her ticket out of debt.
"Those Selfish Aliens" (comedy, fantasy)
Aliens, the government, and fishmen implant bombs in a poor paperboy.
"Time Warp Trouble" (fantasy)
Warriors from feudal Japan inexplicably pop into a high-school classroom.
"The Laughing Target" (drama, romance, supernatural, tragedy)
When they were children, Yuzuru Shiga and his cousin Azusa Shiga were engaged. Azusa aims to make sure that Yuzuru stays hers, no matter what, but Azusa also has a dark secret...

Volume 2:
"Wasted Minds (Dust Spot)" (adventure, comedy, fantasy)
Follows a pair of two bickering government agents, both of whom have special abilities. (A five-part mini-series)
"The Golden Gods of Poverty" (gag comedy)
An unfortunate boy's scientist parents try to use him to make money, but they only succeed in contacting the Seven Lucky Gods, who happen to also be broke.
"The Entrepreneurial Spirit"
A woman leads seminars for a get-rich quick scheme.

Volume 3:
"That Darn Cat" (slice of life)
Takahashi Rumiko remembers having to take care of her neighbor's cat.
"When My Eyes Got Wings"
A couple befriend a sickly child with a secret and his destructive pet bird.
"Wedded Bliss" (comedy, romance)
A wedded couple can only let out their tension from working all day by fighting with one another, until their neighbors threaten to have them moved.
"Sleep and Forget"
A girl relives a past life involving her lover and an evil witch back from the dead in the form of a dog.
"A Cry for Help"
A fairy gives a boy a frightening split personality thanks to the wind-up key she inserts in his neck.
"War Council"
Student councils go to war with one another over a stamp.
"The Face Pack"
A man can change his appearance at will and leads a "masters of disguise" club.

more info here.

The story revolves around Tsukune Aono, a boy who accidentally gets enrolled in a school inhabited by monsters and demons. He quickly befriends Moka Akashiya, a vampire who soon develops an obsession with his blood, and later meets other girls who soon take a romantic liking to him.

On the once-peaceful planet of Industria, constant battles have been fought over control of the planet. Astro is a dim witted but kind boy who tirelessly works to feed his "family," a group of orphaned children. One day, after being fired from his most recent job, the prince of Industria, Bulge, appears in front of him. And even more shocking, Prince Bulge looks and sounds exactly like Astro! One thing leads to another, and Astro now has to take Bulge's place as the heir to the throne of Industria! Suddenly, he's faced with the task of bringing peace and harmony back to this war-torn planet!

- Red Hawk NEO

The Mana Tree, the giver of mana and life for the world of Fa'Diel, burned down nine centuries ago. A war erupted between faeries, humans, and others seeking the scarce power of mana that was left. When the war concluded, the drained Mana Tree slept and throughout the many lands of the world mana was stored in ancient artifacts.

Toto, and his pet Rabbi, have set out on an adventure to restore the world, and its mana, to its former self.

The Lands of Fa'Diel are populated with a large number of different creatures, including humans, faeries, demons, the jewel-hearted Jumi race, plant-like Sproutlings and Flowerlings, miner bears called Dudbears, and shadowy beings of the Underworld known as Shadoles. Fa'Diel is also the home of a host of anthropomorphic animals and objects, as well as monsters such as Rabites, Chobin Hoods, and Goblins.

Adaption of the PlayStation game of the same name.

From Tokyopop:

Fifteen years ago, a set of twins--a girl and a boy--was born to the king of Linevan. Shortly after their birth, a prophecy foretold that when the girl turned 16, she would bring about the end of humanity. To avoid this terrible fate, the king ordered the princess disposed of...scrapped!
She miraculously survived and was raised away from the kingdom that would kill her. But now she has turned 15, and the king's guards have caught wind that she's still alive...and they set out to finish the job!

(From Tranquil Spring) A comedy version of Simoun.

4-koma manga based on Peach-Pit's Shugo Chara! manga. However, this one is being done by the mangaka, Kinomin.

From Del Rey:

Everybody at Seiyo Elementary thinks that stylish and super cool Amu has it all: But nobody knows the real Amu, a shy girl who wishes she had the courage to truly be herself. Changing Amu's life is going to take more than wishes and dreams - it's going to take a little magic!
One morning, Amu finds a surprise in her bed: three strange little eggs. Each egg contains a Guardian Character, an angel-like being who can give her the power to be someone new. With the help of her Guardian Characters, Amu is about to discover that her true self is even more amazing than she ever dreamed.

Contains the side story Shugo Chara! Encore! in volume 12.

Shugo Chara! was awarded the 2008 Kodansha Manga Award for best children's manga.

Welcome to the cursed island of Shina Dark. This island is called home by the dark lord Exoda C. Claw AKA Satan. He's as powerful a being as you could ever hope to meet. Feared and hated the world over for the infinite amount of atrocities he's committed. He's.....actually a really nice guy who just wants to chill out around the castle and relax... After a month long nap he awakens to find that the rest of the world has made up another ridiculous rumor and blown it way out of proportion and that has caused his little island to be crowded with a thousand beautiful girls meant to be his mistresses/sacrifices. Worse yet is that since they have set foot on his island they are all believed to be cursed and are now shunned by their homelands. What’s a couch potato Satan to do with 1000 women who wont leave? Who can say?

From Operation Boredom:

During an eclipse, demon Lord Exoda. C. Crown was revived. He is supposed to bring chaos and destruction to the world. The world is panicking, and as a sacrifice to the demon lord, they decide to send 1,000 girls to the demonic island, Shina Dark. However, in Shina Dark, all the legends are lies. Exoda does not sleep with 10 girls a night, and keep the others prisoners. He does not lust for girls, he does not want to cause mass destruction - he simply wants to live in peace. So when 1,000 girls suddenly show up in his island and refuse to leave, what will happen to Exoda, who simply wants to be left alone?

From Turtle Paradise: After being shipwrecked on a remote southern island, Lina and Co. protect its townspeople from an attack by pirates…. But the island holds a deep, dark secret - and powerful magical forces are at work trying desperately to hide its past. The fate of the world once again rests in the hands of the over-bearing Lina Inverse… For better or worse! Join Lina, Gourry Gabriev, Zelgadiss Greywords, Amelia Wil Tesla Seyruun, and introducing Luke and Millena on a brand new adventure!

From Manga Art:
After Daa! Daa! Daa!, Ruu is now a cheerful youth living in his home, Planet Otto. Then, a confused girl named Miu arrives through a wormhole from Earth. Ruu joins up with her and promises to take her home. Unknown to Ruu, Miu is the daughter of the same people who took good care of him in his stay on Earth.

[From Condensation]: About three girls who transform into rabbits to save people from the Stress Monsters.

A headstrong Snow White lives with her dwarfs; including one who may or may not have feelings for her...