If you're looking for manga similar to Wakaokami wa Shougakusei!, you might like these titles.
When cheerful orphan Pollyanna comes to live with her strict Aunt Polly, Pollyanna's unyielding optimism lifts the hearts of everyone around her.
Orphan Mary Lennox moves from India to the English moorlands to live with a wealthy uncle she's never met. The young girl wanders the grounds of her new home and discovers an abandoned garden that's been locked away for a decade. With the help of a nature-loving local boy, Mary works to bring it back to life. As the seeds begin to open up, so do the hearts of those who come to look upon the mysterious Secret Garden.
Ever since Pollyanna was accidentally sent a pair of crutches instead of a doll, the little girl has learned to be glad about everything. (Her father told her to be glad she didn't need the crutches) Her "Glad Game" encourages those around her to try and be grateful for their own blessings. When Pollyanna is sent to live with her cold Aunt Polly, her optimistic enthusiasm faces its biggest challenge yet- Aunt Polly doesn't see ANYTHING to be glad about!
Mountain girl Heidi's heart belongs to the Alm, where she lives with her grandfather and spends her days with goatherd Peter and his flock of goats. When her relative Dete takes her away and places her in a wealthy household to be a companion to a rich man's wheelchair-bound daughter, Heidi is constantly criticised by the head housekeeper for her unrefined ways. For the sake of her new friend she tries to hold in her overwhelming homesickness, but all Heidi wants is to return to her grandfather where she belongs.
Chihiro Komiya is an energetic elementary school student who was living with his mom. Chihiro is very good at doing housework and chores, and his mother's motto is "No work, no food." After his mother suddenly dies, a man named Madoka Taketori who claims to be his uncle shows up, and asks Chihiro to come live with him. Chihiro initially refuses, but when seeing the horribly dirty state of Madoka's rich home, he decides to start cleaning it. Then Madoka makes another offer to Chihiro: that he comes to live with him, but in exchange Chihiro will do the housework. Chihiro accepts this deal, but suddenly finds himself in a maid uniform.
When Heidi is left in the care of her grandfather, a mountain hermit with a bad reputation, the child falls in love with her new rural home and adores her gruff but good-hearted grandparent. For Heidi no place will ever be home but her dear mountains the Alps.
Suddenly, her life was turned upside-down... Kinaho lived alone until one day, her boyfriend Akito brought with him two young relatives: a pair of brothers who had just lost their parents. All at once, Kinaho finds herself living under one roof with not just Akito, but serious-to-a-fault eighth-grader Toma and innocent five-year-old Haruhi. As the days pass in confusion, this group starts to forge a new relationship: a family... or something like it.
Anne, an imaginative young red-haired girl, is accidentally adopted from an orphanage by a pair of aging siblings who originally wanted a boy to help them work their farm. The happy accident changes everyone's lives for the better.
At the Star Kids Home, a combination group home/orphanage, a disparate group of children struggle with both the everyday issues of growing up and those specific to abandoned or orphaned children. Their one avenue of escape is the Sunny, a junked car that sits a little ways from the home. In the Sunny they can travel the world, go into space, or just find a refuge from the troubles of their world.