The concept of magical girls are present in both Mahou Shoujo Lyrical Nanoha A's and Fate/kaleid liner Prisma☆Illya. In both series, the main character's life are suddenly changed after one faithful day and they in turn become a magical girl with gifted powers. With that gift, they must fight to collect certain magical objects with the help of a mentor.
The main female character from both series are also somewhat naive but are caring, helpful, and cheerful. They also hope to make friends even with rivals throughout the series.
Both series has plenty of humor and drama. However, Mahou Shoujo Lyrical Nanoha A's has a more serious mood especially in later episodes.
They also take place in a school life setting.