The future where the Virus of Death shall destroy humanity awaits. In order for humans to avert that destiny, Raito is asked to travel back to the past. His mission: to make sure a normal high school freshman Tanaka Yuu makes children with his childhood friend Takane Kyouko! (Source: Shogakukan, translated)

4koma spin-off of Hayate no Gotoku.

O-Tsuru (the crane), named because she used to stand on one foot to warm the other, was sold by her parents to become a geisha. She will begin as a shikomikka (apprentice) in an okiya: the house where the geisha live. By doing the commissions of his elders, Tsuru will discover the life of these women. Finally, one day, her turn arrives. She goes to her benefactor's room. Who, by paying the ceremony fees, will bring it into the world of geisha. Tsuru will then take the name of Tsurugiku and become a famous geisha in the world of pleasures. Note: It was first collected in a volume in 1992.

Through his hobby, which is exploring (peeping?) through the spaces in-between, Heisaku-kun ends up falling in love with his neighbor, Fumio-chan. However, it turns out that Fumio-chan has also been spying on Heisaku-kun all this time. Will this uncontrollable pair's hidden love ever be realized?

Eight is a boy who yearns to have a dream school life, for it applies several tests to enter any school. With all this, Eight can not enter any school, except a school that he does not remember having done the entrance exam, later on when he arrives this school will discover a world of super people with ideals and skills out of the ordinary.

Souta, a penniless, phoneless, destitute middle schooler, met a high school girl with a stray cat underneath a bridge... The girl laughed at his minuscule remaining change, and made a surprising proposal with "For this 24 yen of yours, I'll let you buy me," and then...!?

A year and a half later. Finally, they followed the clues to reunite with the supposedly dead hero Zion to reform the strongest legendary party! Now it's time to go find the "Kingdom of the Gods"! (Source: Ura Sunday, translated)

When Konoe Moyako and her little brother Akira were young, he said he wanted to marry her. Naturally, Moyako decided that her little brother was a complete pervert who was obsessed with her. Now that they're both teenagers, Moyako is convinced that she needs to "rehabilitate" him; however, it seems that the "perversion" is entirely in her imagination, and she can't seem to help turning completely innocent situations into creepy ones in her mind!

From Mangadex: Spin-off from History's Strongest Disciple Kenichi. Note: Only read this manga once you're up to at least chapter 313 of Kenichi main series. Released at the same time as Kenichi volume 48 (containing chapters 448-457), Kenichi Plus is a collection of three short stories that will take us back in time… The first story features Tanimoto, as he kindly reminisces his memories of Kano Shou, from the first time he met him, up until Kano Shou last fight… In the second story, we follow Loki and No.20 adventures, as they start and struggle to run their detective agency. But that's when Niijima shows up with a request that fit them perfectly. For the final story, which features Renka, we will follow Pisuke's story, a bird who lived many adventures before ending up as Renka's pet

Yasaka Tokiwa lives in an unusual time, and according to his dreams, it's about to become even stranger. He's been having a dream of a woman called Ri'in ever since the robot, who he calls Makina, came to his home. He and Makina attend the same school, where their other classmates include a secret ninja (Kusanagi Kanata) and a sorcerer (Yata Haruka). When Tokiwa, the robot, the ninja, and the sorcerer rush to rescue the student council president from a demon, the boys find that they've all been having the same dream! What is going to happen to their world? (Source: MangaHelpers)

An all-boys school is good—— Since being recruited into the Student Council by Sawane, we continued our relationship of friends with benefits. Is this taboo? Or is it immoral? Regardless, I don’t care, because I love Sawane. I have Sawane, and aside from me, Sawane doesn’t…… Our distance is far, yet close, so this narrow area here at the school, is perfect for us. (Source: Shogakukan, translated)

Note: The title is a play on the word Kakurenbo - かくれんぼ "hide and seek", except the last part is replace with renbo - 恋慕 "(falling in) love; attachment".