>Kanojo ni Naru Hi: Another
There's some mysterious worldly system that may change people's gender in order to keep balance of genders in the world. MC changes and is in denial about it. He looks like a guy most of the time so it almost feels gay sometimes.
>Unbalance School Life
Everyone in the school except for MC turns into girls, and there's like 5 real girls mixed among them. Everyone thinks it's gay for them to like boys or vice versa, but the manga is actually pretty funny anyway.
>Ani ga Imouto de Imouto ga Ani de
Non-bloodrelated siblings switch bodies. The girl loves the brother and starts making advances when they swap, and the brother gets confused as fuck.
>Ichinensei ni Nacchattara
After an accident MC gets turned into an elementary school girl by a perverted scientist. I haven't finished reading, but it's pretty fun so far.
>Nozomu Nozomi
Guy finds out he likes crossdressing, and somehow turns into a real girl. The opposite happens to his sister. It's a little lewd sometimes but it mostly focuses on the story.