Guys with Kids

Tachibana Yuuichi, who lost his family in a traffic accident, took in his seven year old nephew, Ayumu. Needing to start anew, they move to a small city by the sea, where they meet the warm Kurebayashii Ryou who runs the local souzaiya and is loved by everyone. But in reality, Ryou is completely different from what he seems to be.
It's a beautiful, heartwarming story, focusing on the struggles of three young people trying to let go of their tragic past and save each other in the process.

Asahi is a graduate student, who suddenly had to take care of his older sister’s child Masaki. One day, while he was shopping groceries, he came across Nishino, his childhood friend, who decided to help Asahi take care of the kid. As the time goes by, they become closer.
It's a cute, funny story, full of fluff. It also contains a different, two-chapter-long story. (Which I found hilarious, btw)

Tomoya has been bullied since he was little. The only one who protected him was a good-looking and gentle childhood friend and crush, Kohei.
Years later, they meet again but Kohei has now a kid! Tomoya can't hide his shock. As he sees his friend struggling to raise a child all alone, he wants to help him.
A very cute story about two childhood friends who meet again.

Chiaki and Kazuma are a couple since high school. One day, Tomoe, their free spirited childhood friend, comes to them with tears in her eyes and asks them to raise her daughter a day before she leaves Japan. The couple is dumbfounded but decide to her her.
It's a really sweet story, definitely worth (re)reading.
There's also a prequel available which is also just as cute.

Takemura is a distant, workaholic designer in the planning division. While most of his officemates had given up on interacting with him, his loud co-worker Masaki Natsui is persistent on breaking his indifferent demeanor. When one trip to the convenient store leads to Takemura crossing paths with Masaki and his adopted son, Mori, everything changes for Takemura as he is pulled into a somewhat makeshift family dynamic with the two.

It's a really cute manga about a high school student and the much older housekeeper. If you're okay with that, it's just fluff and worth reading.