From MangaHelpers:
One day, Serizawa fell asleep at work and had a dream about a past love that he wronged when he was in middle school. On the way home, he was involved in an accident, and a woman who knew him called for an ambulance. Now the woman has his phone number, but he doesn't know her identity. Serizawa thinks back over the women he has loved in the past, trying to determine who this woman that has re-entered his life is.

Kang Chan and Seyeon have been close friends since they were young after being introduced by their parents. After entering high school, Seyeon suddenly received a confession from Kang Chan and became aware of Kang Chan since then. Meanwhile, Naeun is displeased with their relationship. The trivial and noisy story of their love triangle and those around them...

A story about a new enthusiastic teacher, Naoki Sakura, who took up his new job in all-girls high school! He became the homeroom teacher of the first years, but the girls in the class contains full of different personalities. He declared to these girls "I want all of you to love one another!" Will he and his students be able to build a teacher-student relationship with that goal!?

With the space program attempting to travel to Mars, 21st century scientists were tasked with warming up the planet so that humans could survive on its surface. They came up with an efficient and cost effective plan of sending cockroaches and mold to the surface so that the mold would absorb the sunlight and the insect corpses would serve as a food source for the mold.
It is now the year 2577 and the first manned ship to Mars has landed on the planet and the six crew members are ready for their mission. But what they find are giant mutated humanoid cockroaches with incredible physical strength. The crew members are easily wiped out, but not before sending a transmission back to Earth. Now, humanity will send elite warriors to exterminate the mutated bugs and claim back Mars.

Note: Was nominated for the 6th Manga Taishou in 2013.

Kentarou is a plain, nondescript college student who has never had a girlfriend or any friends. After getting hit on the head by a wayward ball, he begins to notice that there are increasingly long periods of time in which he cannot remember what he was doing.

One afternoon, he regains consciousness in an apartment he'd never been to before - and sitting next to him is a young man who then tells him "You're being possessed by the spirit of my dead girlfriend"...

Summary by amoxi:
A new big beautiful guy is transferred in Hoshino's class. Wait! He's Ichinose, the troublemaker of middle school. At that time Hoshino has written a love novel between Ichinose and his new stepbrother. When the novel was discovered by a classmate, they make fun of them and triggered Ichinose's wrath. Then ichinose transferred. Maybe was Hoshino's fault? And now he's back!

A collection of stories:

• Hot Gaze in the Cold Weather

• C.5 - The Love Relationship between Mai-chan and Ecchan

• Madder Memory

High school students Kamijou Haruta and Homura Chika are members of a wind instrument club that is on the verge of being shut down. The two are childhood friends and they spend their days practicing hard, while also trying to recruit new members. When a certain incident happens within their school, they work together to solve it.

(Source: ANN)

Sayoko is an incredibly kind, but solitary, young kimono-clad lady who has certain supernatural abilities. She can see ghosts, and she frees them from their places of death by agreeing to let them haunt her instead. As a result, everywhere she goes, she is followed by an army of well-meaning spirits that only she can see. Her weirdness tends to throw any normal people who would have otherwise possibly become her friends.

Inaba is a poor college student who happens to accidentally run over Sayoko with his bicycle.
Sayoko normally is unable to interact with people for long periods of time, because since she is haunted she endangers the health of other people just by being close to them.... But for some reason Inaba is completely fine with being around Sayoko even for long periods of time....

...Just what's going on?

Through the course of unlikely coincidences, a man and woman meet again and again in three different lives. What will become of their love in the world of the immortals?

After her Grandmother, her last family member, pass away her beloved teacher proposes to her. But to her surprise her spouse already has a son - the popular, and kinda mean, boy sitting next to her.

A girl stranded in a small lakeside village deep within the mountains, Mitsuha, and a boy caught up in the oddly orderly chaos of bustling Tokyo, Taki, begin to dream of another, unfamiliar life. Before long, they realize that they aren’t dreaming at all, but actually switching bodies. Separated even further apart than they ever would have imagined, yet still somehow inexplicably connected, they search for the truth behind their strange phenomenon and discover what really happened on that fateful night when the stars rained from the sky.

From Muses Scans:

Clothing designer Yuuki; cool and mature company president whom he met online, Hasegawa; and a frugal university student, Makabe. Hoping to start a communal life together! Both men unconsciously thrown into a home wafting with pheromones!
Older vs Younger x a little devil’s love triangle!
A room sharing romcom filled with exciting and passionate happenings.

Kotaro is always writing letters to Eliza, the girl he likes, but never has the courage to give them to her. One day, a hungry demon called Colchette wanders into Kotaro's garden, attracted by his collection of letters, and encourages him to confess his feelings to Eliza.

From Omari's Sister:

"Pika Ichi" is the story of two painfully shy teens who love yakuza movies. An incident at school pushes them over the edge, and they decide to drop their mousiness in order to dispense some "justice."

A worthless husband and his carefree wife. 54 short stories of their heartwarming, funny, and sad life. Winner of the Tezuka Osamu Cultural Prize and Japan Media Arts Festival grand prize Kono Fumiyo gives us this heartfelt short comedy.

Forced by her mom to get a job, Emma (a self-proclaimed NEET) scores a job drying sheets for a strange family...who turn out vampires in exile. When the cute son takes a liking to her, what's a girl to do?

In a fantasy world, fighter Tatsumi sets out for the Capital to earn money for his starving village, and finds a world of unimaginable corruption, all spreading from the depraved Prime Minister who controls the child Emperor's ear. After nearly becoming a victim of this corruption himself, Tatsumi is recruited by Night Raid, a group of assassins dedicated to eliminating the corruption plaguing the Capitol by mercilessly killing those responsible.

From Easy Going Scans

Young Ma Go-eun and her father are about to be evicted from the haunted house they've run throughout the years. But Go-eun is not about to let the park owner demolish their haunted house and her memories of her childhood and her mother. She resolves to go to the United States to surpass trials and get a million dollar cash prize awarded to those who can survive a stay in Ghost Jack's House.

The romantic relationship between a naive yankee girl and a boy with seemingly no common sense.