The world of anime is miniscule compared to the expansive manga universe. While there are some amazing manga adaptations, due to the sheer volume of manga, there are many that are left unexplored onscreen.
Sometimes, it's understandable that a fantastic series has gone under the radar – Keiko Tobe's With The Light features excellent storytelling, art, and character development, but follows a mother trying to raise an autistic child in a society that doesn't always understand her family's needs. Not only is it focused on a niche topic, it also lacks a conclusion thanks to the author's untimely death. However, there are some wildly popular complete series, like Vagabond by Takehiko Inoue, that seem like they should have been made into an anime ages ago.
Sometimes manga adaptations don't work as anime, but these manga feel ripe for the jump from the page to the screen. Every season, new manga adaptations appear on the anime scene, so it's entirely possible the shows on this list – and other amazing manga out there lacking an anime version – will get a second life in anime form someday.
In HERO's Horimiya, Kyoko Hori and Izumi Miyamura are two high school students whose classmates don't see them as they truly are. Though Kyouko looks like she has everything under control, she's actually under a lot of pressure at home, as she's responsible for watching her younger brother and taking care of the house. Meanwhile, Izumi appears to be a gruff, brooding nerd, but he actually is just quiet and bad at studying – oh, and he has a tattoo.
The manga is about how the two get to know the real Kyoko and Izumi, and they slowly grow close. It would be amazing to see such a nuanced love story adapted into an anime.
Autism doesn't receive a lot of attention in manga or anime. While there are characters in a variety of series who fans believe are autistic, With The Light: Raising an Autistic Child by Keiko Tobe is the only series to explicitly deal with the subject.
With The Light tells the story of a young mother raising an autistic child named Hikaru, depicting both the struggles and joys of their life together. Not only does it provide great insight into autism and other disabilities, it's also a window into how Japanese society deals with special needs.
To its orphan inhabitants, Grace Field House seems like a paradise. Everyone is treated with kindness and respect, works and plays hard, and gets adopted as soon as they turn 12. The kids are forbidden from leaving the orphanage, but one, day two children break the rules and discover a horrifying secret: Grace Field House is not an orphanage at all, but a place to raise humans as livestock for a race of man-eating demons.
Yotsuba&! is by the same manga artist who created Azumanga Daioh, Kiyohiko Azuma. Rather than focusing on high school students, Yotsuba&! follows a little girl and her father as she discovers all the new and wonderful things about her world. It's similar to Sweetness & Lightning, a manga and anime about a child discovering the joy of cooking along with her father, but with a little less pathos and a wider scope than food.
Unfortunately, there are no plans for an anime adaptation, as Azuma doesn't believe the themes or style would translate effectively into animation.