If you're looking for anime similar to Magical Girl Lyrical Nanoha, you might like these titles. All recommendations are made by Anime-Planet users like you!
Karin Hanazono’s life isn’t easy; she’s an orphan, her grades are poor, she’s terrible at sports and in general, she is miserable. After the death of her precious pet, Karin met a strange boy named Kazune Kujyou – an encounter which changed her life forever. For Karin, as she then discovers, is a goddess! Now, with the help of Kazune and his cousin Himeka, Karin will learn how to use her powers and protect her new family. As she learns more about herself she must also face the mysterious people who share her powers, and discover what it is they are fighting for.
For Niwa Daisuke, turning 14 should be accompanied by romance and the promise of new adventures into adulthood, but instead comes with a surprising revelation: all male children of the Niwa's bloodline inherit the powers (alter ego) of Dark, a phantom thief, upon their 14th birthday! Now, in addition to his ever-present quest to win the heart of his childhood friend Risa, Daisuke must commit acts of thievery (with his doppelganger Dark controlling his body), to steal mysterious pieces of art for unknown purposes. For Daisuke, his growing pains are just beginning!
Both D.N.Angel and Nanoha follow a young protagonist that has to learn how to use their powers to collect dangerous magical objects and prevent them from harming others. They also each have a rival with a dark past that challenges them in their goals--in D.N.Angel, Daisuke has Satoshi, the young prodigy police detective that wants to capture Dark, and Nanoha has Fate, a rival magician who is also collecting the Jewel Seeds. Their relationships are similar in each show, which gives a similar feel to each despite their diffences in setting and plot. Nanoha is definitely aimed more at a "otaku", young adult crowd with its ecchi moments and attempts to do something new with the Magical Girl genre, while D.N.Angel is more of a straight shoujo with a bigger focus on romance (and the relationship between the two cute guys, instead of the cute girls). But if you're looking for another magical transformation show with a rivalry in the middle of it, then both of these shows should be enjoyable t you!
The story is set in a peaceful time on a dreamlike world entirely made possible by science. Five years ago, the world's energy crisis was solved with the creation of the "Manifestation Engine." Akane is a 14-year-old girl who lives an impoverished but happy life with her little sister and grandfather. However the tranquil daily life that Akane enjoys is shattered by a threat, and she vows to face it in the red battle suit that wields immense power.
Vividred Operation is a short series that is basically like a "magical girl" anime complete with transformation scenes and awesome weapons. Both Vidred Operation and the Nanoha series emphasize friendship as bonds that bring the main characters together; also both series are kind of similar in that the main protagonist wants to find out more about the mysterious other main character.
Once there lived an eccentric author called Drosselmeyer who wrote grand tragedies - one of them was the tale of a prince who sealed away an evil raven by breaking his own heart into tiny pieces. However, before the story could be completed, the author died and the tale took on a life of its own. Now, in a town where fiction and reality meet, the story continues on its tragic course with Ahiru, a duck who transforms into the beautiful Princess Tutu in order to restore the prince's heart. But will Ahiru's act of love be enough to defy the story's terrible destiny and lead to a happy ending?
Both are magical girl shows where a solo magical girl fights against (and tries to befriend) a solo dark magical girl. This leads to some similar relationship dynamics. The two shows are somewhat similar in regards to how dark they get, but Princess Tutu is generally much sillier than Nanoha. However, I still think that if you like one you should give the other a chance.