Smells Like Green Spirit
Guy who likes crossdressing ends up being found out by his bully. It’s actually a really bittersweet manga about coming out and acceptance.
Caste Heaven
Ijimeru Aitsu ga Waruinoka, Ijimerareta Boku ga Waruinoka?
Bullied teacher becomes the bully after getting his former bully's daughter in his class
Yoarashi Ni Warau
Don't bully teacher :3 yandere classmate will protect
Miss Guillotine
If Sailor Moon and her friends were manipulative, sociopathic bullies
Free in Dreams
Girl being severely bullied ends up meeting a white haired stranger in her dreams, who helps her get revenge on her bullies. Si Yoon is SO toxic. It kind of evolves into this not-super-healthy, lovesick relationship between FL and ML after the bullying storyline finished. They're both overly dependent on each other and 2nd ML needs to back the f*ck off. Like you know her boyfriend doesn't like you, you still have feelings for FL, you have the audacity to preach without practicing. Get off your high horse and just leave them alone.
At the End of the Road