Another reaction could be that she becomes sad and starts to cry. If Lily is sensitive, Harry's yelling could really hurt her feelings, and she might retreat into herself, which could then make Harry feel guilty for his outburst.
She might be shocked at first. Since Harry is yelling, which is out of character for him in many cases, Lily could be taken aback and not know how to respond immediately.
Lily could get angry in return. She might not tolerate being yelled at and fight back, leading to a heated argument. This could escalate the situation further in the fanfic, with both of them saying things they might regret later.
She might get angry right back. Ginny is a strong - willed character. So, if Harry yells at her unjustly, she could stand her ground and yell back, not willing to be pushed around.
She could also become cold and distant. Instead of engaging in a shouting match, she might simply walk away and give Percy the silent treatment. This can be a powerful reaction as it makes Percy realize that his yelling has pushed her away and he has to make an effort to fix things.
Another reaction could be that Sakura becomes more determined. His yelling could fuel her desire to prove herself to Sasuke, whether it's in terms of her strength, her loyalty, or her understanding of him. So instead of being deterred, she uses it as motivation to grow and change in the eyes of Sasuke.
Peter might be initially shocked and a bit scared. After all, Tony is like a mentor to him. But then he could become defensive, trying to explain his actions or point of view.
Hinata might be very hurt. She's a sensitive person, so Naruto yelling at her could make her feel small and sad. She might start to doubt herself and her abilities.
Snape might initially be taken aback. He's used to students being intimidated by him, so Hermione's outburst could shock him into momentary silence. Then he might retaliate with his usual sarcasm, trying to put her in her place.
On the other hand, he could feel ashamed. If he realizes that he has truly made a mistake, seeing his father so angry and disappointed could make him feel bad about himself. He might lower his head and not say anything, with a look of guilt on his face.
Ginny might be heartbroken at first. She could retreat into herself, spending a lot of time alone in her dormitory or in secluded places around Hogwarts. She may cry a lot and avoid socializing with their mutual friends.
Snape might initially be taken aback. He's not used to students standing up to him so forcefully. He could glare at Hermione with his cold, dark eyes, trying to intimidate her into silence.
Alternatively, Ginny could be very mature about it. She might respect Harry's decision, even though it hurts. She could choose to step back and give Harry the space he seems to need while secretly hoping that he will change his mind in the future.