I am looking for manga with MC being bully in the past and was traumatize by it. The MC seek revenge against the bully but start to fall in love without realizing it.
Manga I have read
-Kimi no sei (the MC confess his love to the girl he used to bully in the past, she agree to go out with him for revenge)
-Koe no katachi (no revenge)(the MC bully a girl, but then feel guilty and went to look for redemption)

I am okay with non-manga comic type:
-manhwa
-manhua
-webtoon
-webcomic

Hope you guy can share with me great manga
Thanks in advance

I only know one that might fit:
Masamune-kun no Revenge

Hmm.. Maybe Kimi no Koto nado Zettai ni ?

You could try the first 2 stories from Renai Rubi no Tadashii Furikata. It's yaoi, but it's got exactly what you're looking for.

I second this as that's immediately what I thought of when I saw this thread.