Looking for a BL where one of the ML gets bullied by someone other then the other ML

Can be bromance like Weak Hero Class 1 and Dogko rewind as well. 

I don't know whether this drama has enough severe bullying for what you are looking for, because there is no physical violence involved. But the way, the class mates make fun of their relationship was a bitter watch to me:

Love Class (season 1)

Night Flight

The Boy Foretold by the Stars

Be My Favorite

The Eighth Sense

Thundercloud Rainstorm (other ML isn't the bully, but he doesn't like him in the beginning)