If you're looking for manga similar to Carat!, you might like these titles.
Protagonist Shurutsu Kenichi, caught up in his cousin's machinations, debuts as a “female middle school student” idol “Neushwanstein Sakurako” even though he's a boy. Fighting alchemists' evil plots and being an idol makes for a really busy life!!
I'm just a normal highschool boy but somehow I ended up having to become a magical girl to protect the world. But whenever I'm in my transformed form (girl), I develop feelings for my male best friend?!
Kaito Odagiri is a normal fifth grade boy who can hold his own in a fight and loves to show off. This attracts the attention of Makoto Kaibara, a boy at Kaito's school who reveals to him that he can use magic, but he needs Kaito's help to protect the peace of their town. Kaito jumps at the chance of being a magic-wielding superhero, but his excitement turns to horror when he realizes that he'll be protecting the town dressed as a typical magical girl under the name Thrilling Pink. Although initially reluctant, Kaito soon discovers that there's more to being a magical boy than simply looking cute in a skirt.
Loosely based on One Thousand and One Nights and other children's fantasies. Princess Seblan was brought up as a prince to save her life, and she later turns into a real prince who lives happily ever after with his wife. Together with his sometimes-sarcastic magical horse Hendek, Seblan ventures out into the world of fairies, dragons, and other mystical creatures.
Ayumu was murdered by a serial killer – at least, he was. For after the mysterious Eucliwood Hellsythe revives him, he changes from a human to a zombie, much to his dismay. Now, in addition to being unable to die, Ayumu must see to the whims of his supernatural, silent companion – but things continue to get worse from there. As once Ayumu accidentally steals a magical girl named Haruna's powers, he is tasked with the embarrassing, obnoxious task of being a magical girl – err, boy– in her stead! Then with the addition of a hostile vampire ninja to his household, can Ayumu manage to maintain his new home life, fight against attacking monsters, and track down the person who killed him all while attempting to keep what little dignity he has left in tact?
Ayumu Aikawa is a zombie resurrected by a necromancer named Eucliwood Hellscythe after being killed by a serial killer. As he tries to make the best of his undead life, he encounters a Masō-Shōjo (a pun on "mahō shōjo", meaning magical girl) named Haruna and inadvertently takes her magic powers, being forced to become a Masō-Shōjo (and thereby crossdress) in the process. With Eucliwood, Haruna, and a vampire ninja named Seraphim living with him, Ayumu helps battle demons known as Megalos while trying to figure out the mystery behind his own death.
"Love makes a girl stronger." Saki Uno is working hard as part of the new idol unit, Magical Twin. The one she admires most is Mohiro Mikage, who’s the older brother of her idol unit partner Sakuyo, and he’s also a member of the top idol unit STAR☆PRINCE. She would be willing to do anything for him, and one day, those feelings brought on a miracle. Saki ended up turning into a magical girl when she strongly wished to protect someone... But what she turned into wasn’t exactly what she was expecting...