1. Aoyama has freckles. (I've already mentioned this one.)
2. The male Todoroki siblings will kill you if you hurt Fuyumi in any way.
3. Monoma has a shrine dedicated to Shinso.
4. Tokoyami has a pet budgie.
5. Hawks likes animals like any animal.
6. When Rappa gets upset/worried/scared he clings onto the closest thing (Usually Tengai or Setsuno) or finds Tengai.
7. When Endeavor is upset all his children sit with him and make jokes until he is happy.
8. Angry Shoto is scarier then the rest of them when angry combined.
9. Katsuki likes headpats.
10. Kaminari helps Kirishima dye his hair after he realises Kirishima's hair ain't actually red-
11. Shigaraki and Dabi threaten to kill each other when flirting.
12. Mic compliments Aizawa whenever he can and Aizawa acts like he hates them but he actually loves them.
That is all my headcannons for now