One idea could be a crossover where Mob and Midoriya meet. Mob's psychic powers and Midoriya's One For All could lead to some really interesting team - up scenarios. Maybe they have to face a villain who can manipulate emotions and they combine their powers to defeat the villain.
It's fiction. Kensuke's Kingdom takes you into a fictional world crafted by the author's creativity. There's no real-life basis for the story or its elements.
There's also 'Growth Together'. This fanfic shows how Deku and Todoroki support each other during tough times at UA. They face challenges not only from villains but also from within the school. Their relationship develops as they help each other overcome these obstacles.
A great crossover often involves a good balance of the powers from both series. For example, when Reigen from Mob Psycho 100 somehow gets involved in a My Hero Academia battle. His con - artist skills could be used in a really unexpected way, like tricking the villains into believing he has a powerful quirk.
One great 'Team 7 x My Hero Academia' fanfiction is 'The Crossover of Heroes' which combines the unique abilities of both universes in an exciting plot. It has great character interactions that stay true to the original personalities.