If you liked the Tonari no Kaibutsu-kun manga, the Anime-Planet community thinks you'd like:
Yuiko loves animals, but given the overly-aggressive way she tries to show her love for them, they always run away. One day Yuiko meets a strange boy named Leo who seems to be more beast than human; his fierce eyes frighten everyone away, and he harbors a dark secret: when he's threatened or sees blood, Leo loses control and behaves like a wild animal. Can Yuiko tame this wild beast, or will he run just like all the other animals she loves?
The biggest thing that makes these two manga similar is the lead males. Both are scary-looking high school students that are feared by all their classmates. However, in both their cases a girl is able to discover that although they sometimes get violent when provoked, the guys are actually very friendly and goofy. If you enjoyed one of these manga because of the lead male, then you'd enjoy the other for sure.
President of the Student Council at the almost-all-boys Seika High School, the hard-as-nails Misaki Ayuzawa works every day to make life easier on the small population of co-eds who have enrolled there. Though an unholy terror to all things male during school hours, in order to provide for her impoverished family, she secretly works after school at a maid cafe in Akihabara. However, when campus hottie Usui Takumi wanders into the restaurant during her shift, suddenly she finds her reputation in school at his mercy...
These two have lots of similarities from tags to story plot. Both are Rom-Com Shoujo and have female main characters think of the male main characters as their rival. Male main characters have a mysterious personality and annoying attitude when the talk comes to their family/past.
Four gorgeous guys, one fabulous mansion and one challenge - turn the landlady's niece into a perfect lady and live rent free; fail and their rent will triple! Surely this task will be no problem for Ranmaru Mori, Kyouhei Takano, Takenaga Oda and Yuki Tohyama, who are lauded as the princes of their high school and have girls dropping at their feet daily... right? The boys' dream of rent-free living comes crashing down when they meet Sunako Nakahara, the girl they must transform. Sunako has devoted her life to solitude, preferring the company of anatomy mannequins, horror movies and the darkened seclusion of her bedroom to the presence of the ‘dazzling creatures' that cause her to have violent nosebleeds. Flushing her out into the light might prove to be more than the boys can handle!