Idk what your fanfic is about so idk if I’m being helpful or not but here some suggestions. Hurt/comfort, angst, fluff, flashbacks, past lives, soulmate bond, blind date, drunk confessions of love, secret relationship, break up/make up, roommates, hero to villain, sympathetic Villain, silly entertaining goons, badass hero, the character that is oblivious to another character’s feelings for them, enemies have to work together, alternate universes, mental health struggle, and a character struggles to accept themselves (gender, sexuality, etc).