From Tokyopop:
Sergeant Keroro is the Captain of the Space Invasion Forces Special Advance Team of the 58th Planet of the Gamma Storm Cloud System, sent to the planet Pokopen (aka Earth) to collect intelligence for his planet's invasion force. He is also a frog. After his ship crash-lands in the planet earth, he takes shelter in the Hinata household, but the two kids, Fuyuki and Natsume, find him and take away his alien weapons. When his people discover that the Pokopenians are aware of him, Keroro is abandoned - left to fend for himself in this hostile world. But he's not alone - four other pre-invasion agents were are also lurking on Earth.

Note: Won the 50th Shogakukan Manga Award for children's manga in 2005.

Long ago, the God Aigis sealed away the devils that caused havoc in the human realm. Now many thousands of years later the Demon God, Tiamat, has come to the human world seeking to destroy all humans using the very devils that Aigis had sealed away so long ago. One of the first to fall was the imperial capital where their prince, who is descended from heroes, had no choice but to run away and watch as his homeland burned. Now he must do what he can to survive Tiamat's onslaught and recruit allies in order to take back his kingdom.
Will he live to see the day his kingdom is free of Tiamat's hands?

Shinichirou decides to look for a job in order to pay his rent, and his teacher suggests that he work for someone at their house, doing housekeeping. However, the person who hired him was Sakuya, a girl who is the 37th head of the Shimazu family, and her job is to exorcise and eliminate unwanted creatures. Shinichirou accidentally releases one of the creatures that Sakuya captures and they cooperate to catch it. A story of comedic creature hunting begins!

Note: Read this if you are confused about the chapter numbering.

A short (two-three pages bimonthly) gag manga about two best friends, one of whom (Ayame) is in love with the other (Amane). Each chapter follows the hijinks of Ayame's advances towards Amane, which usually end up in comedic failure.

Zashono Academy is unique in all the world. It has 54,000 students and this allows for some VERY specialized clubs. There are clubs for just about everything you can think of... and then there's the Eiken club. No one seems to know just what it's about, but they do know that it's filled with some of the most bodacious babes ever to be brought together! ...and then there's Densuke. Densuke is a little awkward and clumsy and he always seems to be in the most compromising positions with all the other club members. And all he really wants is to be with the cutest girl on campus, the lovely Chiharu. Will he ever be able to get away from the uncomfortable club activities and let Chiharu know what's really on his mind?

Nakama is a librarian who loves reading light novels, and he looks exactly like Manaka, the male lead of Ichigo 100%, but taller. One day, he saves Aya, a frequent customer, falling from the ladder while trying to reach the top of a bookshelf, and accidentally does some ecchi stuff to her. He immediately falls in love with Aya and her strawberry panties. However, as she mistakes him for Manaka, so does Satsuki, her love rival. A new love triangle between Nakama, Aya, and Satsuki.

"Hey, you said you wanted a sister, right?" First year highschool student, Toujo Basara, was suddenly asked by his father and fell into a state of panic. On top of that, the eccentric father told him he will be getting remarried. He then departed overseas after bringing Basara two beautiful step-sisters. But Mio and Maria's true forms are actually the newbie Demon Lord and a succubus!? Basara was almost entered into a master and servant contract with Mio, but a "reversed" contract was formed by mistake, and Basara is now the master!? Moreover, Basara is being hit by ecchi situation one after another due to the contract, but Mio's life is being pursued by other demon tribes and hero tribes!! The most powerful contractor's desire action drama begins!

Spring has arrived, and at this school, a teacher and young budding girls. What will be their fate?

Mahoro is a battle android created by Vesper to defend the Earth against alien invasions.
Having fought long and hard on behalf of Vesper, she only has 37 days left before she stops functioning. However, if they remove all her battle functions and equipment, Vesper can lengthen her life to 398 days. As thanks for her hard work, Vesper lets Mahoro choose how she would like to spend her remaining time.
She chooses to work as a maid for a boy named Suguru Misato.

Noa Kagura is a cross-dresser who gets asked out by Shinobu Takada, a boyish girl on their school's karate team.

From Easy Going Scans:

Asuma Eiji has the gift of psychometric power, meaning he can touch people or objects and see their history in images and words. Most of the time, Eiji is just a delinquent high school kid who hangs out with his friends and neglects his schoolwork. However, his psychic abilities have brought him to the attention of police inspector Shima Ryoko, who often calls him in to help out with difficult cases.

Currently, there's a serial killer loose in the city who has just claimed his sixth victim. He kills young women, contorts their bodies into odd shapes, and uses spray paint on them. With Eiji's psychic help, will Ryoko be able to catch the murderer?

This is a sequel of Psychometrer Eiji.

Takahashi wakes up one day to discover he's turned into a woman. Curious about what it feels like to have sex as a woman, he asks his friend Hirukawa if he wants to have sex.

“I’m an adult now. I’m going to sleep with 122 men!”
In his highschool years, Taeho made a ridiculous promise with his childhood friend, Shin Sari; to give each other their first times! Taeho buries this promise in his memories as he matures and eventually forgets it. However, Sari is still fixated on this promise when they reunite in college!

A collection of oneshots about monster girl wives (and more!).

In a dark future, rival warriors of warring sects persecute nonbelievers and die for their faith. But a disillusioned young novice and a deadly gun-toting priest may be about to change all that…

Young Capria has completed her studies at the Arsenal School and has begun her internship with the Elysia Unification Council under Father Garrincha. But no lessons could prepare this sheltered novice for the outside world, where rebels battle against the dreaded "Testarotho." Heretics are tried and burned at the stake, warring religious factions battle for power, and the common people live a miserable life in feudal servitude. Can she bring a spark of hope to a world filled with destruction and madness? Maybe if she lives long enough!

A guy waiting at a bus stop one hot, summer night meets a girl wearing what he thinks is a rather peculiar outfit.

Makabe Masamune has changed himself greatly for a single reason: he wants revenge. Contrary to his past, he has worked hard to become good-looking in order to carry out this goal. Faster than anticipated, he even meets the target of his revenge the first day after transferring in.. Adagaki Aki! He wastes no time beginning his plan, but revenge doesn't come easily.

There is a strange breed of mechanical creatures, aptly called “Machines,” who will, on the condition that their Host never love another person for as long as they live (else the debt will be paid in blood), grant their wielders fortune and prosperity. And where a Host has betrayed his Machine, you are sure to find a member of the mysterious Gari family, wielders and hunters of Machines, in the ensuing carnage…

So it was justifiable when the Gari family was dispatched to Shakunage High School to covertly investigate a brutal murder perpetrated by the spindly hands of a Machine… But it wasn’t so justifiable when Hanare Shizuma, a youth with an agenda of his own, enrolls at the High School soon thereafter, hell-bent on conducting his own investigation – and soon meets the head of the family of hunters, shockingly enough, a girl his own age. But little do either of them know that their encounter will set the cogs of fate spinning rapidly into motion…