From MangaHelpers:
Sagara Soma is a hardcore gamer, who spends basically all of his time playing or thinking about games. Since he was a child, he's thought of how great it would be to really live in a game world. One day, when he breaks a promise to his cousin Maki in order to play video games, his wish comes true. "New Communicate Online," also known as "Neko-Mimi-Neko," is the game he was playing at the time. Neko-Mimi-Neko is well known for its trick quests, occasional unfairly high level enemies, and many bugs, all of which combine to make players die over and over again. Now that Soma seems to literally be a starting character in the game world, will he re-spawn after death, or actually die? Luckily, he knows just about everything there is to know about the world of Neko-Mimi-Neko, so he may be able to make the unfairness in the game work to his advantage.

Washed up on the shores of a deserted island at the edge of the East Blue Sea, two men from different backgrounds unite in their shared thirst for adventure. One of them, Portgaz D. Ace, will follow in his infamous father’s footsteps as the fearless captain of a pirate crew. The other, Masked Deuce, becomes the reluctant first member of Ace’s Spade Pirates. Survival is not enough for these seafaring buccaneers, as together they seek treasure, excitement, and a route to the New World.

From the author of the manga "Daten no Inugami - Slashdog", a new bishoujo action series!

From Yen Press:
After being soundly thrashed by the hero Emilia, the Devil King and his general beat a hasty retreat to a parallel universe…only to land plop in the middle of bustling, modern-day Tokyo! Lacking the magic necessary to return home, the two are forced to assume human identities and live average human lives until they can find a better solution. And to make ends meet, Satan finds gainful employment at a nearby fast food joint! With his devilish mind set on working his way up the management food chain, what will become of his thirst for conquest?

Interactions between this world and the one ruled by the demon lord have grown increasingly common. Unaccustomed to teaching the denizens of another world, Itou Kazuki becomes perplexed when the demon lord's daughter, an avid fan of shoujo manga, transfers into his class. "If you make my daughter cry, I'll destroy your world."

Elfie, an elf, spends her days busy with work, so she has a diminishing number of friends and no boyfriend... Feeling the limits of her situation, she finally explodes with dissatisfaction: "I want to get married!!"

After hearing her war cry, a flower in her room turns into a faerie. That faerie tells Elfie how she can be happy. That is... "Let's go marriage hunting, and get you married!"

Elfie takes the faerie's advice and tries various means of marriage hunting, but will any of them work out!?

The beautiful lady, Louise, has memories from her past lives. And there are 7 peoples' worth of lives (moreover the villain's role). Louise, who has always met the bad end of getting stabbed to death, has decided that she will live this life peacefully. However, Louise has been assigned as Prince Emile's instructor! And so, she struggles with teaching the extremely shy prince who shuts himself up in his room. In her 8th reincarnated life, she will do anything for a happy ending!

Exploring the mysteries of the reincarnations and the secrets behind her previous deaths, this is a high tension comedy with the reincarnated lady and unique characters!

After dying in a traffic accident, I find myself standing near an unfamiliar lake. My body won't move, I can't hear my voice, and when I try to shout in confusion, words that I never expected come out!"Get one free with a winner."I-it seems I've turned into a vending machine...! I can only do what actual vending machines can. It's impossible to move by myself, and there's no way for me to have any meaningful conversation-how am I going to survive some fantasy world's dungeon like this?!

(Source: Yen Press)

Ars, the prince of the Kingdom of Karitz, who was called the strongest wizard, died at a young age. But on the verge of death, he uses reincarnation magic. Reincarnated as Wals Sai, a slave with the best body! Wals, who became the escort of a princess in a small country, became a matchless slave who used his best body and magic to crush all enemies! From "Become a Novelist"! A fantasy adventure by "the strongest slave", opening !! * "Become a novelist" is a registered trademark of Hina Project Co., Ltd.

The story happened at the dawn of the Tang dynasty. Nobody knew the peaceful and prosperous capital Chang An had a really experienced demon fox, Duan Mu Ming De for its biggest brothel's owner. The shounen onmyouji Bai Yu Mu, the best onmyouji among the younger generation of his onmyouji family, masterful at slaying demons and being vengeful, was forced to reside in this demon nest. There, he got acquainted with a seductive fox, a cold and distant wolf, a tsundere gold crow, a Virgo hedgehog and a two-faced weasel...at the same time, a larger conspiracy is brewing in the dark, in the capital that never sleeps, in which fires are lit every night. Meanwhile within the prosperous Chang An, the Rebellion of Anshi threatens to erupt..

From Yen Press:

A disillusioned young man in search of “something” stumbles into the weird and wacky world of Wonderland, where, as “Alice,” he is thrust into a murderous game of “Kill the White Rabbit” by command of the ruler of the land, the Queen of Hearts. But while Alice rails against the role that has been forced upon him, he has little choice but to comply. For in Wonderland, not sticking to the script can have deadly consequences…

An extreme marriage proposal!

When I wake up in a car accident, I'm in a distant future!? Feathers and horns... and from four beautiful boys who call themselves "gods".

"You are the only human female in this world. Please give birth to my child!"

Huang Bei Yue is an assassin that gets transported to another world thanks to a mysterious jade, boundless beast!
Now she resides in the body of a 12 year old, who happens to be the king's sister, who is constantly bullied!
"Now how shall i take my revenge?"
Original Webcomic (Chinese)

Yukino Amaishi signed a contract with God to save her sister. She was then reborn in a different world as Lefina Eilferia, the daughter of a duke and the Crown Prince's fiancée. After successfully completing the objective of giving the heroine and the prince a happy end, Lefina, who played the role of the villainess, ends up working in the castle as a maid.

A post-apocalyptic world. Following her last order, the mechanical soldier Ria has been fighting an endless war for over a hundred years. With the people she was meant to protect gone, and her comrades-in-arms lost, Ria spends her days fighting alone.

Then, a human appears before her once more..!?

One day, Yadoya Kenta, who was working for a black company, dies of exhaustion. When he wakes up, he finds that he has been reincarnated not as a hero in another world, but as Tohri, the son of an innkeeper in a rural town! This time, he wants to work moderately and relax! Surrounded by a kind family and lively customers, the slow life of an innkeeper's son begins!

Being a teenager is never easy. Especially for a centaur! Himeno is a sweet, shy girl, who like many teens her age, struggles with the trials and tribulations of attending high school. The difference is she's a centaur; but she's not alone. In fact, all of her classmates are supernatural creatures, sporting either horns, wings, tails, halos, or some other unearthly body appendage. Yet despite their fantastical natures, Himeno and her best friends—the dragon-winged Nozomi, and Kyoko with her spiraled horns—are down-to-earth, fun- loving teenagers who grapple with issues of life and love in a mostly normal daily school setting.

Note: Won the 8th Comic Ryujin Award.

The story evolves around Chandra Nalaar, a young firemage who trains at the Kerald Keep in the mountains to learn how to control her powers. But life isn't that easy because the Order of Heliud, a sect of mages bent on imposing their draconian law across the land, is now also expanding their dominion to the woodlands near the Keep. The Order's ever-increasing influence is an affront to all Chandra holds sacred: freedom, individuality, the right of self determination, and most of all, the right to blow things up. So the young mage is sent on a mission to find out more about the order but her impulsive spirit is about to cause her a whole lot of trouble...

When playing a virtual reality game called Cang Lan, Xiao Wan gets pushed off a cliff. She ends up in another game world. What will happen to Xiao Wan?

Having been torn from the earth in ancient times, Planet Mamango is now re-approaching the earth after a lapse of 5 million years. One night, a private detective named Ban Shunsaku encounters a murder, and meets boy researcher Shikishima Kenichi, who holds the key to solving the case. Shikishima discovers that a stone from the Planet Mamango generates huge amounts of energy. Making a rocket out of the energy stone, Shikishima sets up an exploration team and departs for Planet Mamango. The rocket heads straight for Planet Mamango under the command of Shikishima, along with Captain Butamo Makeru, Ayame and Momiji, who are cabbages created by the captain, a rabbit named Mii, and Ban Shunsaku. In due time, the rocket lands on the Planet Mamango, where the group finds a “The Lost World,” an ancient environment where dinosaurs walk about and ferns and cycads cover the ground.

Note: The most widely available version (including the english one) is the 1948 one, directly published by Fuji Shobou. This is a remake of an unfinished series Tezuka wrote for the Kansai Kyouron Shinbun in 1946, which has been lost. He remade the series once again in 1955 for Bouken Ou under the title "Zenseiki Hoshi", but this version too has been lost.