Recommendations

Very bromance heavy. This is one of many The Lost Tomb reboots/sequels, however this one and Reunion: The Sound of the Providence are the best ones of the bunch (in terms of story plot and level of bromance). I love the bromance between Wu Xie and Xiao Ge in this, one of my all time faves!
But this is about tomb raiding, and it may not be everyones cup of tea. But I do recommend.

If you want more bromance dramas in ancient china times, then this is worth checking out.
I love the special relationship between the three different main characters, a powerful eunuch, a low ranked official, and an imperial guard. They are so different but work together so well, worth checking out.

Both dramas cover infidelity. But, the cheaters in One Spring Night capture your heart! The romance is great.

Both lead actors did a great job to bring out the depth of their characters. Theme of a cheating couple is obvious and similar to this drama. But, it’s taken to another level and does not feel as trashy as the current drama. Cheaters are not glorified in Secret Love Affair.

Similar that both dramas are about being your younger self again...The only difference is, in 18 again, its a man; in Sumika Sumire, its a woman.

Both the male and 2nd male lead are the same in both drama's and both are high school based.

Both have this dramatic feel about them
Intense sacrificial love between the leads
both around the era when japan invaded Korea
cool sword fights
"warrior gives everything to protect the girl"
although note that the movie was made in 2009 so give the direction/production a pass

Both of these Dramas have time Travel as a theme.
The Main characters of both dramas goes back in time.
Both these shows involve a killer on the lose.
Both shows are similiar, the protaginists knows what will occur in the futre.
Both shows makes it apparent, how the past affects the future.

Both Precise Shot and Youths in the Breeze have cute bromances between the leads, both of the dramas also undergo various deep emotions while the leads fall for each other in a very beautiful way.

Malpractice issue.

Good/ great surgeons.

Good doctor hated/ opposed by someone of higher position.

Doctor saving the person he hates at the end.

Good series, good casts. Great medical drama.

Malpractice issue.

Doctor being transferred to another hospital

Though D-Day focused on disaster that happened to Seoul, the operation and how doctors treat patients are similar.

Good medical teamwork.

Doctor suffering from illness. Great surgeon.

Both with great casts.

Both medical drama with good doctors opposing to someone higher.

Both good dramas.

Both good storyline. Though D-Day focused on disaster that happened to Seoul, the operation and how doctors treat patients are similar.

If you like Dr. Romantic. D-Day is one great series for you.

Both with a bit of romance, with good medical team.

Doctor being transferred to another hospital.
Doctor suffering from PTSD. Great surgeon.

Both with great casts.

Both MLs are from weak to strong. They both become the strongest in their universes. Xiao Yan appears as Flame Emperor in the Great Thousand World which is the world The Great Ruler takes place in.

Psychological thriller, intrigue and revenge. Moon Chae Won in the cast. Song Joong Ki is a brilliant, dedicated and affectionate student, until he meets the person who it would make your life hell. He is betrayed and decides to take revenge by approaching someone important in the life of the ex.However, he did not expect that he could develop other feelings for this person. Was the thirst for revenge stronger than love?

Both dramas have police officer ML and investigative storyline. No romance but totally thrilling drama! Though Memorist's ML has special power. In both dramas everyone looks suspicious. In short both are enjoyable!