Recommendations

Both are BLs about the relationship between a human ML staying in a room haunted by the other ML who is a ghost.

Both are Thai BLs about the relationship between a human ML and a ghost ML who died tragically in high school.

Both are BLs in which one of the MLs dies tragically and the other is given a chance to go back in time and try to undo what happened, only to learn the two have a predetermined fate. Both MLs have a somewhat forbidden relationship (stepbrothers vs. age gap). Both dramas have a bittersweet/sad relationships as the leads cannot be together.

Both are Thai BLs in which one of the MLs is a tutor to the other who has a rougher attitude.
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Both drama are about bullying in school
In both drama ml is great fighter
Both drama are funny and also gives you a lot of motivation for studying
Most disgusting and horrible bullies (i hate them)
Best action scenes

Dark high school series vibes with bullying and fighting between students. There is also a sense of mystery and a strong and complicated (non-romantic) relationship between the 2 main male characters as they navigate the school system.

Both are psychological thrillers BL dramas where there are killers and deception involved. There are hints of supernatural elements as the story goes back and forth in time for both. Both shows are written by the same author Sammon who specializes in writing crime and mystery stories.

JoongDunk the actors star in both BL dramas which have crime and killers in both. There is deception and uncovering of secrets as the drama progresses. Joong is the serious character and Dunk is the playful character in The Heart Killers and their roles are reversed in Dare You to Death.

Both BL dramas follow a group of friends that has one (or more) of them trying to kill the rest while all of the group's dirty secrets are revealed as they try to find who is the serial killer.

Complex story of innocence and revenge. How tragedy affects even those who stay at home. War and Officialdom. Cause and effect on people. Love story mixed in between.

Same writer, both revenge-driven dramas centered around money and corruption. MLs who are passionate and stop at nothing to reach their goals.

It's weird recommending this because TFF is not about ex going back together.
And also TFF is not done yet , but the leads in both have the dynamic of being destined together, and the plot of talking things out.

They both deal with families issues and ladies trying to find a good husband. They are both history fantasy and deals with stories of different characters.

The protagonist is a vampire who awaits the reincarnation of the woman he loved 100 years ago and who was killed to save him. Very similar to Goblin. You will definitely like it.

Both dramas are asadoras and I highly recommend them. If you’ve seen one, you’ll want to see the other since they both have Sugisaki Hana, who is great in both.