From MangaHelpers:
One day, Matsui Sakura receives an invitation to a "Revenge Game," and decides to attend. At the location indicated, she ends up locked in a dorm-like building with four of her classmates. It appears that the Revenge Game is being run by a wealthy classmate, Saionji, who was bullied so badly by some of the students that it ruined his life. Now he is taking his revenge, in a brutal game that allows him to have one of his former tormentors killed each morning.
However, Sakura--a lonely, quiet, orphan girl--does not understand why she is there, unless it was due to her inaction in stopping the bullying of others. She's also the only one who received an invitation, while the others were abducted or tricked into attending. What is the final purpose of this game?

Ten contestants agree to put their life on the line to have a chance of winning 50,000,000 yen. To win, they must survive 10 days inside the prison...

-Tenji

UFO Robot Grendizer is the third entry in the Mazinger Trilogy by Go Nagai, following Mazinger Z and Great Mazinger. This particular incarnation was illustrated by Gosaku Ota and published in Boken Oh, Otomodachi from October 1975 – March 1977. It follows the adventures of Duke Fleed, the sole survivor of an attack on the Vegan Empire, who defends his second home, the Earth, from the Vegan attack, together with the giant robot Grendizer.

From Storm in Heaven:

A collection of short stories.
Chapter 1: For a long while now, I've been prone to losing things. It's the things most important to me that I lose, and it's always after I lose them that I realize it. And then, they're suddenly returned to me.

Story 2: Love Letter
A woman has just been discharged from hospital due to her successful eye surgery. As she steps out into the world, she sees her blind self...
Story 3: All of Sully/Lily
A man believes that people he loves should have spare bodies. His daughter happens to have one...
Story 4: Airport
A man drops off a pregnant woman to the airport...
Stroy 5: Fetish
An injured girl has met a man that thought her appearance were "cool"...

Fourteen-year-old Kouichi Hayase’s life has always been a mediocre one, if not dismal. However, those days of being bullied by classmates and escaping to a fantasy of being a hero are put to an end when a certain “accident” bestows on him a girl and a gigantic humanoid robot called “LINEBARREL”. The extraordinary power that Kouichi obtains puts him and everything around him on a sudden rollercoaster ride of battles, intrigues and friendship! During the course of his adventure, the boy starts to learn what life has to offer; he meets new friends, bids farewell to the old ones, but most of all he now has considerable responsibilities and is forced to confront the world around him.

In an organization of professional killers called Thanatos, there exists an elite assassin. His skills are such that he reigns supreme over all the others in the organisation... And he is also the killer of the protagonist's family. The protagonist swears on his life that one day, he will rise through the ranks of Thanatos and challenge the man who took everything from him.

Fighting for the position of No. 1, the curtain rises on a battle fought with blood over blood!

The series follows the adventures of Sabu, a young Edo bakufu investigator traveling with the blind master swordsman Ichi. In their travels, they assist the common people in solving mysteries and righting wrongs (usually committed by bandits or corrupt officials). Sabu is engaged to Midori, the daughter of his boss, who works as a police officer for the Tokugawa shogunate.

This series won the 1968 Shogakukan Manga Award.

High school junior Wakaba Sakimoto is a normal girl, no matter how you look at her. Everyone around her is thinking about the future, but Wakaba still doesn't know what she wants to do. Then one day, she meets voice actress Touko Hosaka by accident, and Wakaba's future changes in a big way...

[from JManga]

A run-down Tokyo at the end of this century. Here lives the young teacher Tsunagu who has to deal in his poor life with all sorts of bad-ass students and suffers a lot from his relationship with the violent lover Akira whose heart he knows he'll never have.

In spite of Akira's threats Tsunagu refuses to give up his teaching job because he wants to be there for a few good students like Aoitsuki. However, unknown to him, angelic-looking Aoitsuki isn't what he seems.

Meanwhile, there is Shou...

All of Keiji's bodypiercings are the symbol of a secret contract, which stipulates that all his needs would be completely taken care of by two twin brothers, Sou and You, in exchange for his becoming their pet.
However, the appearance of Miyama - Keiji's first actual friend - starts changing things. For the first time, Keiji finds it difficult to keep this dark secret buried, and the thin balance he tries to maintain unknowingly starts crumbling bit by bit...

Feelings like growing fond of someone, trust, friendship, love... each swaying feeling is depicted in this famous series, now in completed version!

Original webcomic A story about a guy who lost everything, and a girl who had nothing

From JShoujo Scans:
A manga about love between porn stars. Amidst all the rampant sex and graphic situations, lies a story which depicts the harsh nature of the porn industry.
Based on the life of Japanese AV actor Kato Taka.

"When winter came, you swept away my sadness. When it passed, the memories of you lingered in my mind." A love that transcends time between a winter spirit and a girl broken with sorrow...

My world has always been a colorless bubble. But she burst it with nothing more than her smile and her words, turning it into a kaleidoscope of vibrant colors.

From Girls' Generation Scanlations:

Bad drunk, four-eyed tsundere, Takahashi Kyouya, returns to his hometown after four years of absence to find his childhood friend, Hino Motoharu, waiting for him. Oblivious to Kyouya's feelings towards him, Motoharu is more than happy to have Kyouya back. However, love that sparkles in the boiling hot night in the midst of the Karatsu Kunchi festival doesn't seem to stop flowing.

This story describes a man named Nan Gong Sheng who gets caught in a terrible conspiracy while trying to learn about his life story. Forced to stand against his people, he starts to try and find a ancient book called "Tian Yuan Ce" in an attempt to stop a terror plot. While following the world in the mysterious book, characters with mysterious powers started emerging. Feelings within the demons have also started arising.

Natori Nono is a very tough schoolgirl. She lives with her widowed mother Ayame and her younger brother Takumi in a very small apartment, where she does all the chores. Her boyfriend wants money from her, because he's really poor, too. But one day, Nono discovers that her mother remarried! She married Ichijou Hayato, the owner of the 'Ichijou Group'. Now, Nono lives there (in unaccustomed riches) with her mother, her brother, her stepfather AND her new stepbrother: Ichijou Kasuomi (his father calls him Omi-kun)!!! At first, Nono thinks Kasuomi is not nice. But what will happen next?

Included in this manga are two short stories called Sayonara Marigold and 130 cm Kara Merry Christmas.

One ruler...One schemer...and...One assassin The kingdom of Juushin is suffering at the hands of a cruel emperor. In order to stop his father's rule of tyranny, the crown prince will enlist the aid of a legendary assassin with reasons of her own for wanting the emperor dead.

From LINE Webtoon:

A medical student passionately falls in love with a fallen goddess during his volunteer abroad in Nepal, and he desperately tries to fight off destiny to save his love.

Nakano Mayaka's Sayonara Sakura is a bittersweet unrequited love story about a young man who is secretly in love with his adopted older sister and how he comes to terms with the fact that she sees him as family and is going to marry another.