You Look Quite Pretty
In which our mc is a dangerous guy nicknamed the "Reaper" because he is so strong. Because he is kicked out of school so often, he is given only one more chance at going to school, but this time, he has to dress up as a girl. He then meets some friends and they do stuff. In this manhwa, our mc is a quiet guy and the supporting characters are great. His female friend is well written, having a dramatic childhood, but gets over it and becomes stronger, with the help of our mc and their other friend. This other friend is also well written, since although he is also immensely strong, he has no friends, and tries to make friends with others, but fails until the teacher tells mc and his/her friend. Eventually, everyone gets along, which helps the plot along. There is also another character who tries to find out who the "Reaper" is, which helps add some drama, while keeping the tone of this story light and fresh.
Rhapsody of Mulan
In which our mc is killed by his best friend during a war and gets reincarnated into his sister's body. He then joins the military to help his family, because there is a war going on. Mc, however, has to dress up as a guy because girls aren't allowed to join the military. It started out well. The art is beautiful, and the characters are more or less there. However, when reading the raws, I feel as if it got worse and worse every passing chapter.
Wolf Boy and Cinderella
In which our mc has a curse. He turns into a girl in the morning and a boy at night. He tries to fix this by attending a school where he can find a book on how this curse can be broken, but meets a dog-like and troublesome boy. Honestly, this kinda sucks. The guy is really selfish, like, can you get anymore selfish? He stops mc-san from breaking the curse because "he likes mc better as a girl." Dude, if you really like someone, should you stop them from doing what they want. And should gender really matter? Well, I suppose this is Japan and they have serious prejudice against gays so yeah. But still, really?
About a Lazy High School Guy Who Woke Up as a Girl One Morning
In which our lazy main character gets turned into a girl for no good reason. Follow our mc as he finds out how it is to be a girl.
Kenja No Deshi Wo Nanoru Kenja
W-juliet
In which guy has to dress up as a girl to per sue his career in acting. One of his peers find out and they proceed to love each other.
Kanojo Ni Naru Hi
In which guy turns into girl via "emergence". His best friend has the fear of women and guy, now girl, tries to help him over it in the most unconventional way ever, all while they fall in love.
Tensei Kyuuketsukisan wa Ohirune ga Shitai