Depends. Is your preference towards teasing, like Karakai Jouzo no Takagi-san?
Towards revenge and what happens afterwords, like Fukushuu Kyoushitsu?
Disparaging home environments like what's found in Sekai Oni?
Regardless, bullying generally takes a backseat to main plots. Some manga with it as a key point that I can think of are Sundome, Saiteihen no Otoko, and I want to name a third one, but I just can't. Bullying is almost never in manga unless it's a major plot point, and even more rare is it staying in the story for more than a dozen chapters.