Bad Buddy reminded my of Love Sick, which I would deem one of the original Thai BL dramas. The main characters of both dramas are in a school setting (College/High School) who seemingly have no relationship to each other according to the people around them. The relationship growth from no relationship to friendship to lovers can be found in the dramas.

It's the prequel to part 2. Both are short and hilarious, I recommend watching part 1 if you want to understand the flashbacks but you would still understand the drama if don't want to. They got a lot of same actors from the first season which is always a plus.

Both dramas have a similar plot line about three men with different personality handling a baby.

Both couples go through a lot to be together and face an illness.
(BOTH ARE REALLY SAD).
Have a box of tissues ready

Both dramas have a similar plot with differences. Both have an adopted daughter, they try to move on with their lives but the past is blocking their way.

Both of the main actors in Because of You also acted together in 15 Years to wait for Migratory Birds

Similar plot line. the father has an affair and as an act of revenge the woman switches the child, then neglects the child she took but the child grows up a bright child.

Both female leads undergo plastic surgery due to money issues and both have a guy friend who realizes their feelings after the female lead leaves.

Two best friends start living together and realizes their feelings for each other.

Both dramas are about not so good students getting into a well known college. When I first saw Dragon Sakura I automatically thought about God of Study