Total Recommendations: 5
Watching 5 cm per second movie reminded me of toki wo kakeru shoujo a lot. Both are romance movies about separation of lovers. They both also have amazing artwork.
They are both same director's work, if you liked the style of one, you'll likely enjoy the other. They have also similar stories, since they are both about separation of lovers who try to communicate with each other. However, the artwork of voices of a distant star is not as good as 5 cm per second's.
Both series have female protagonists surrounded by beautiful men and they are both school comedy and romance. Even though i like Ouran High School Host Club more, if you enjoyed The Wallflower, you really should watch Ouran High School Host Club.
They are both Yuu Watase's works, so they have similar love triangle, drama, romance and adventure elements.