Total Recommendations: 6
Campione! and Strike the Blood are pretty similar. Both protagonists are seemingly normal high school boys who came to wield an enormous power before start of the series. Also, the plots focus more on how they gain experience using their powers than on how they came to obtain their power in the first place. Despite being WMDs in human form, Godou and Kojou try to live normally and completely fail to do so while struggling with their controlling their summoned creatures and strange female acquaintances.
So far, they seem pretty similar. In both, a high school boy slips and falls, resulting in a leap back in time. When he "arrives" there, he is mistaken for his grandfather and consequently receives a place to stay.
Midarizaki and Minamoto (the respective male protagonists) are both elites of the Japanese paranormal/esper organizations, and are both forced into a makeshift family as the "father" of abnormal children.
The relationships between the characters in Komatta Toki and Keishichou are quite similar.
Although Arachnid is Shounen and Kyou kara Hitman is Seinen, they are both about a (relatively) normal person who gets in the way of an assassination and becomes an assassin himself/herself.
They're both about a demon king/queen who isn't a stereotypical "big bad". The Maou in both doesn't advocate violence, and is instead interested in helping humans. Plus, both Maoyuu and Shina Dark are comical.