If you're looking for anime similar to Joshikousei Nobunaga-chan!!, you might like these titles.
Megumi was a normal kid. He enjoyed getting into fights and mixing it up, and one day he did so in defense of a wizard who was being attacked by bullies. His reward was a magical book that was supposed to grant his wish. The mischievous demon inside the book decided to play a prank on Megumi, though, and instead of turning him into "a man among men," he became a girl. Fast forward to five years later, and Megumi is now entering high school, a tumultuous time for even normal teenagers, let alone a girl who is trying to figure out how become a guy again...
Centers on a 52-year-old government worker involved in a car accident who finds himself reborn in a world like an otome game.
The fiercely competitive, yet hapless 'arch rival' of Ranma Saotome, Kuno Tatewaki, comes across a mysterious egg that he believes may hold the power of the mysterious and legendary phoenix - and therefore could give him the means to finally defeat Ranma in combat! However, in true Kuno misfortune, the egg accidentally hatches on the top of his head, and refuses to budge. The sharp-beaked creature quickly begins to wreak uncontrollable havoc in a rampage all over Tokyo, with Kuno unwillingly 'attached' and along for the ride. It's up to the rest of the crew to take on the challenge and bring the brutal bird back to Earth, and save the helpless Kuno from his destructive new companion.
Mahiro Oyama was just a normal erotic-game loving dude…until he woke up one morning as a woman! Turns out his mad-scientist little sister, Mihari, tried out one of her new experiments on him…with a disastrous outcome, as far as Mahiro’s concerned! But Mihari is as determined to study him as he is determined to go back to his shut-in, game-playing life, and one thing’s for sure…life is going to get a whole lot weirder from here on out!