If you're looking for anime similar to Fortune Arterial: Akai Yakusoku, you might like these titles. All recommendations are made by Anime-Planet users like you!
Aside from being harem anime based off a visual novel, the story begins with a protagonist transferring to a new school. Eventually, he joins a club that acts as the center point where he will establish or build on his friendships, with the females in particular. The main heroines hold this club very dear to their hearts, and with the assistance of the selfless protagonist, their collaborative actions in the club better the lives of living beings. Romance also blossoms while working together.
Both of these anime involve vampires (though Fortune Arterial is more vampire-focused, whereas Itsuka Tenma no Kuro Usagi has other fantasy elements as well). They both spend quite a bit of time on things not directly related to the main conflict - such as romance and school life. Both have school as a central setting. And, of course, both seem comfortable with bits of fanservice here and there. Though that last bit could be a turn off if you're anything like me.
The art is similar - fairly bright and bishoujo. Unlike most other vampire anime, these two steer away from a very dark atmosphere.
Granted, I only made it halfway through Itsuka Tenma no Kuro Usagi, but I'm fairly confident thant fans of one anime will like the other.