If you're looking for manga similar to Gridman Universe, you might like these titles.
Six-graders Boco, Junichi and Joe were enjoying their summer vacation. It was strangely rainless summer, but other than that, it was just like another summer. Three boys knew it was their last summer together. Same summer, deep inside a mine tunnel in New Guinea, an investigation team found something. No one knew they were creatures...terrifying creatures.
Insecure Otis has all the answers when it comes to sex advice, thanks to his therapist mom. So rebel Maeve proposes a school sex-therapy clinic.
One day, an unidentified monster suddenly came out of a volcanic crater near Mt. Fuji, and was given the name "Vulcanus". Lava spews out of its entire body, and as it grows and evolves, the enormous beast's body leaves nothing but scorched earth along its path... Then it makes it to the capital city of Tokyo. Meanwhile, Ichiro Ichinose is a 39-year-old bachelor whose dreams have been shattered and now simply spends his days meaninglessly. After attending a classmate's wedding ceremony, he happens to reunite with his childhood friend Kanata Aida, but after she tells him something that he couldn't possibly understand, the beast arrives and things quickly take a turn for the worse...
Five crime scene investigation interns are tested when they must solve the murder of a schoolmate.
Joon-sang moves to a rural city in South Korea. On one day, Joon-sang soon falls in love with Yu-jin. Their love is cut short when Joon-sang loses his memory after a serious auto-accident. Joon-sang's mother has Joon-sang brainwashed so he will not remember his painful memories. As a result, Joon-sang's memories prior to the accident are erased. Joon-sang's mother decides to move to the United States with Joon-sang. Both his friends and teachers are told that Joon-sang is dead. Ten years later, Joon-sang returns to Korea and Yu-jin sees him on the street, prompting her to put off her engagement to childhood friend Sang-hyuk. Little does she know that Joon-sang is dating her friend and sometime rival Chelin.