Recommendations

Both of these dramas have similar main characters, fake relationship and contain funny scenes.

Based on the same Manga.But the story follows only the basic outline of the manga and all the other things are messed up like character development, emotions ect.In my view if you love the Japanese drama then you are going to hate this film.

Based on the same Manga.First adoption of the Manga,, but the ending differs from the Manga as the Manga was on going at that time.

The Lost Tomb, The Mystic Nine and this one is all base on the same novel series.

It is base on the same novel series. I would recommend watching Mystic Nine first.

Mystic Nine is the prequel on the same novel series. It is also very very good.

In both dramas we follow the lead protagonist as he get's hired in a big company. It's interesting because we get a glimpse of how a Korean company works (conformism, hierarchy...)
While Jang Geu Rae is not qualified for the job ang introverted, Chief Kim is talented and extraverted.

Both shows involve protecting/saving a kid and "pull at your heartstrings". It's rare for me to find shows like these but I really enjoyed both and there was a lot of suspense and twists in both.

In each drama, the lead heroine is desperatly seeking a husband.

Hilarious, heart warming, and so very relatable. These two dramas share the same breezy and comedic tone, and both dramas experiment and play around with a fresh format with which to tell their story. Reply 1997 perhaps feels a bit more familiar compared to your standard kdrama, while The Lover feels more like a sketch comedy show- think SNL, only more cohesive and consisting of more genres than just comedy. Both aired on less popular networks, both of these dramas have a similar and unique way of carving their way into your heart. (They also both feature gay character(s), which is definitely a notable feature for Korean shows!)

Both dramas centers on socially awkward characters and their desire for a domestic life.

Both dramas centers on marriage and the heroine's desire of domesticity.

They both have: smart female protagonists who dress up as men in the beginning of the story; intricate planning and court intrigue as they battle their way to the top; multiple love interests; etc.
Empress Ki is a much better fighter than Queen Seon Duk as an individual, but Seon Duk was up against a more intelligent foe and had some brilliant planning.

The protagonists of both dramas have somewhat of the same feeling. The drama has to do with crime and investigating. Both protagonists goes out into the field, even though they are not meant to be. For both protagonists, there is a "sidekick", a female character that helps them and is "used" to help solve the cases they are doing. The Female characters dislike the protagonist at first but ends up warming up to them near the end. The dramas both have somewhat of the same plot. If you like one, I recommend watching the other as well.

Both involve friendship and romance among a group of friends in the 1990s. Both with the theme of youth and things they learnt in the process of growing up (e.g. What they lost or gained while growing up, the responsibilities they will have to take up upon turning into an adult)