The "bittersweet, mysterious story" revolves around Chocolat Aikawa, a chocolatière who runs a shop called Chocolat Noir. She can grant wishes to the troubled people who visit her shop -- if they give her something precious in exchange.

In the Chocolat no Mahou (The Magic of Chocolate) series:

V.01 - Chocolat no Mahou
V.02 - Bittersweet
V.03 - Creamy Sugar
V.04 - Dark Spice
V.05 - Evil Essence
V.06 - Fruity Flavor
V.07 - Guilty Crunch
V.08 - Honey Blood
V.09 - Ice Shadow
V.10 - Jewel Syrup
V.11 - Knocking Egg
V.12 - Love Flake
V.13 - Melty Night
V.14 - Nutty Carnival

One day an ordinary 2nd year high-schooler named Usami Yuu accidentally encounters Takano Hitomi, a big girl with a scary look. Turns out she's glaring at him, but why...!? Although Hitomi looks scary and awkward, she's actually a kind and adorable girl who simply wants to become more sociable. This is a story containing happy, heartwarming slice-of-life comedy!

32-year-old Futaba Kiryu is a manga artist that writes for a weekly shounen magazine. Her latest ongoing manga is a romantic comedy, "Bocchi no Ore kara Riaju no Omaera ni Ittoku" (A Loner Like Me's Got a Lot to Say about You Normies out There) or "Bottoku" for short. It is a best-seller and has an anime adaption on the works. But the truth is, she's completely clueless about romance. The days go on as she continues on working on her manga with her manga assistants, but soon, one of her assistants, Hiro Asakura (she dubs him as "Assassin" because of his cold and intimidating demeanor), and the anime scriptwriter for the "Bottoku" anime, Kitamura Kyosuke (social media dubs him "The Tactician" for his notoriously clever execution in the anime he's worked in) grow an interest in her and eventually make a move on her. How will Futaba fare in this love triangle when her knowledge of romance is next to nothing?

The story of a big and a small girlfriend

Links:
Artist’s Pixiv: https://www.pixiv.net/member.php?id=14807885
Artist’s Twitter: https://twitter.com/sheepD_

Katsutoshi Umiyama is a young teacher of 25 years who is designated as responsible for the men's club volleyball school. The women's club, however, is in the hands of the beautiful Maho Kawashima. When Umiyama accidentally gets too close to a club girl, Ai, the student does not seem to be upset, but ...

When his father re-married, Kazuichi was a timid boy who was easily bullied by his younger stepsister Yami. Through hard work, Kazuichi has become a handsome young man who's the president of the Archery Club and admired by everyone. All in an effort to impress Yami as a reliable older brother, or as something more?

This is the story of Niihama Shincirou, who collapsed after being ravaged by a black company and woke up to find that he had been sent back to his second year of high school. When he wakes up, he finds himself in a time leap to his second year of high school. His high school life …… was gray and shady, but he’s sure he can start over now.
The beautiful girl of his dreams, Haruka Shijouin, whom he met again over time, is even more innocent and cute than he remembered, and above all, she has been staring straight at Niihama.

“I feel like you’ve changed a lot from the Niihama I knew yesterday. You’re still kind, but you’ve grown up, and that’s wonderful!”

If I could change the future, I would definitely save her life after she took her own life after being severely bullied. With the adult mentality and corporate power that I’ve acquired, I’m going to take my revenge on my second youth with her–!

A-rank adventurer Alec meets Shiori, a woman with the mysterious title of "household mage." Shiori, the low-rank magician, is able to prepare warm baths and delicious meals on their adventures with her strange use of magic, providing an all-too comfortable environment that would be unfitting to call an ordinary camp. Though she has thoroughly won over the hearts of Alec and his companions, she has a secret. (Source: Mangaupdates)

I, who should have died after being hit by a car, was born again in another world.

However, I was born in a shady minor family that used magic and controlled wooden puppets called the Marren Clan.

Possessing a strong interest in magic since my previous life, I spend my time zealously studying magic to the point where even the people in the vicinity draw back.

One day, I heard I was to be married to my little sister when I turned 16 in accordance with the traditions of the Marren Clan and decided to flee to the city.

For now, since I have the strongest magic, I guess I should idle around making only enough money so that I don’t have to work for my whole life.

"I want to grow up quicker, so I can date Minato-san."

Akira Minato inherited his grandfather's coin laundry.
And so, the middle-aged former corporate drone, Akira, peacefully ran the well-loved coin laundry.
One day, a high-school student, Shintaro Katsuki, enters the coin laundry.
Despite the difference in age, they quickly became friends.
However, Shintaro suddenly finds out that Akira is gay…

Yuuta Sato accidentally discovers that childhood friend Rinko Uenohara contracted a very rare illness called the "Kissing Disease". The disease forces the person to kiss someone of the opposite sex at regular intervals or die! Yuuta decides that he is going to keep her alive no matter what. Will he succeed? What will the others think when they find out about the two!?

Toono Ao failed to get into college and became a ronin, studying for next years exams instead. To better study for them, Ao moved out to live on his own into an apartment near his cram school. It's not much, but it's a place to call his own. But not long after moving in, a drunken lady finds her way into his new home! It doesn't matter how hard he tries, she just continues to make herself at home and take advantage of him. This is not okay! ...Or is it? His humble castle is no longer his own. Onee-san is invading!

This is a collection of short stories depicting the beginnings of love by Nakamura Hinata. Four cute and tender stories to bring a smile to your face. 

I was reincarnated into the body Cecilia Silvie, the villainess of an otome game.
According to the plot, what awaits me in the normal route is either a slow, painful death or an instantaneous one... Essentially, every route leads to my demise.
Then I'll change my fate! And that's why I decided to become a man.
However, I made a mistake during a certain event, and the story began to head down an unexpected path...?

Hakobe Narumi is an expressionless high schooler known as Stoney. The highlight of his unnoticeable existence is following posts from the popular selfie poster "Efa" on social media. But it turns out "Efa" is his studious and popular classmate Mitsuha Koto?! The slightly erotic, adolescent, selfie, romantic comedy between an Iron Walled Selfie girl and a stone-faced boy begins!

From Friendship Scans:

Beginning of 16th century, Alexandra was captured by slave traders in Ukraine during one of their many raids. When the traders arrived in Greece to sell the female slaves, a young handsome man named Mateus bought her and promised to give her true freedom. He hired countless teachers, scholars, and palace ladies to train her into the one perfect woman of her time.

Mateus's kindness has caused Alexandra to deeply fall in love with him, and she secretly wishes to be his concubine. But cruel fate! Mateus has already promised her to his best friend, who is Suleiman the Great, Emperor of the Ottoman Empire! Mateus promised Alexandra of true freedom, but where is freedom when she is in another man's harem and can only look at the one she loves from afar?

Not willing to endure this agony, Alexandra promises herself that one day, she will free both of them from their bird cages. But Mateus is the Grand Vizier, a power only second to the Emperor himself. So Alexandra must become the most influential concubine in order to have any hope—which also means bearing Suleiman's son. However, Suleiman already has a son by another concubine, and this woman is determined to keep her son as the only prince and only heir.

Thus begins the story of a slave that becomes the story of one of the greatest empresses of all time, Alexandra, the woman who would one day be known as Roxolana, Empress of the Ottoman Empire.

At the age of eight, I realised I had reincarnated as the nefarious last boss of an otome game, Queen Pride. Her fighting strength is high because she’s the last boss who will fight with the capture target, and her superior cunning wits make her the most powerful first princess in a matriarchal country. Since she brings misfortune to all that surrounds her, what awaits is a future of ruination! …really, wouldn’t it be better if I died?

In this case, I’ll avoid destruction from the capture target and freely use my authority and cheat abilities to save everyone!

Note: This manga is continuation of the canceled manga, be sure to read that one first (check the related tab)

Ryou Sagimiya has a rare condition called TSS, Transsexual Syndrome. While touring Tensei Academy Ryou meets Nagisa Minakami, another student with TSS and decides to enroll in the school.

Ryou Sagimiya, who has a rare condition called "sexual change syndrome", admires Nagi Minakami, who he met on a school visit, and enrolls in Tensei Gakuen, where Nagi attends.

A mixed (physical) crossing love comedy!

Known for "Muchuu sa, Kimi ni", Wayama’s first serialization in a commercial magazine is a comedy set in an all-girls school about a Japanese language teacher, Hoshi-sensei, and the carefree play that his students involve him in.

The story starts when Kagawa, a student, delivers the class journal to Hoshi-sensei.

As the students play word chain game "Shiritori" in the form of drawings in the remarks column of the journal, Hoshi-sensei becomes troubled...

Kenzaki is a delinquent who saves her classmate Nakajima from some bullies one day, but Kenzaki still has yet to tell him that she has a crush on him.

Links:
Author's Pixiv: https://www.pixiv.net/member.php?id=479833
Author's Twitter: https://twitter.com/TATSUBONi