If you're looking for manga similar to Seibutsu Suisei WoO, you might like these titles.
Sayo and Nao are childhood friends and neighbours, but Sayo has been in love with Nao for years. With Nao being a year older than her, Sayo finds it difficult to confess her love for him because she believes he only sees her as a little sister. But when Nao tells her he's moving away, it's now or never...!
Ao and Keita, who attend the same high school, live next door to each other and have been childhood friends ever since Keita moved in when they were in middle school. Even though they're just friends who always goof around together, Ao suddenly notices that Keita has been looking cool lately...
“If you want a boyfriend that bad, I’ll go out with you.” Growing up next-door neighbors, Reita Kikuchi and Makoto Sakurai’s parents are friends, and the two of them have known each other forever. But one day Makoto is suddenly thrown into a relationship with that narcissistic and self-absorbed playboy, Reita—her old childhood friend!
Reiko wants to meet an older boy that lived in her neighbourhood 6 years ago. When he moves next door she is very happy. But the gentle boy she knew seems to have changed into a different young man.
Karina's childhood friend Ikumi-kun had moved away in primary school, but he is now returning because of his father's remarriage; not only that, they are next door neighbors! The volleyball club that she has joined as a manager of course includes Ikumi, but also another childhood friend, Yasu, Ikumi's older stepbrother Miyuki-san, and the demon-like Arisaka-senpai, all members with rich personalities. What will become of Karina's high school life?!
Strange accidents always seem to happen around Hako Natsuno—so much so that she’s been dubbed the “Queen of Bad Luck.” It’s hardly surprising then that a naked alien prince falls from the sky to tell her that out of all the girls in the universe, he’s come to Earth to mate with her. Does this mean Hako’s luck has changed, or…?
Aoi and Isumi were childhood friends who often played with each other; but before they knew it they drifted apart and became high school students. In the past, Aoi confessed to Isumi; however, for some reason she cannot remember his exact response. And so the two end up getting into a fight over a trivial matter...