(A/N: Fixed Mei's backstory.)
As you can tell Izuku is having a childhood friends storyline and that has a big backbone for writing romance. Give them a strong background to work with.
Ochaco Uraraka
Backstory: One of Izuku's Main friends she believes he can be a hero, she also lives in a poor household, so she wants to help her family in any way she can
Tsuyu Asui
Backstory: The big sister Izuku wishes he had. While she does believe in his dream to become a hero, she does not want him to get hurt.
Mina Ashido
Backstory: She is the most popular girl in School, she introduced Izuku to her friend group and they quickly became his biggest friends.
Toru Hagakure
Backstory: She is practically the twin sister of Mina, she practically adores Izuku and she is extremely protective of him.
Kyoka Jiro
Backstory: Self-Proclaimed goth, Jiro tends to be aloof, but she is always there when you need her.
Momo Yaoyorozou
Backstory: She is from a rich family, she considers Izuku as a puppy in human form, make no mistake, she may act cold and brash, but she has a big heart.
Mei Hatsume:
Backstory: She is one of Mina's friends. And she also develops a somewhat of a overprotective sister side towards Izuku. She tends to keep to herself unless she is with her friends, or she can be found working on her babies (robots).
End of Harem.