The Saiki K manga ended. It wrapped up the storylines and gave a satisfying conclusion to the readers. Although it's over, it still holds a special place in the hearts of fans.
Nendo could be a great addition. His simple - minded yet loyal nature can add some humor and unexpected twists. For example, he might accidentally almost expose Saiki's powers while trying to be helpful in a situation involving Teruhashi.
One common theme is Saiki's struggle with his powers. In many fanfics, he tries to hide his psychic abilities from others while still having to use them at times, which leads to comical and tense situations.