Recommendations

Same leading actors, a somewhat similar plot-line - JG is historical while TBD&W is Modern - TBD&W is the better drama in my opinion.

Both 20th Century Boys and Death Note are based on an action genre manga series.

Both deal with families and their problems in a tonally similar way and they also both have a murder mystery at the center.

Very similar plot - both are "undercover" in sorts - Iljimae is the better one in my opinion. Both have Lee Jun Ki as the main actor

Both dramas are about the main characters hiding thier identity and carrying out justice during a politically turbulent period in Korean history.

This is a "what if?" story which puts a twist on the folktale of Chun Hyang and Mong Ryong. It's very short and worth the watch. Recommended for those who liked this drama.

Both tell the different stories of teens dealing with family, love, violence, and high school. Gloomy Salad Days is a lot darker then Hormones.

Girl disguises herself as a boy, is surrounded by boys, and one of the guys is oblivious to her actual gender and thinks himself to be gay.

Both are historical dramas with some of the best bromance I've seen in dramaland.

Both feature main characters out for revenge and have some interesting swindling scenarios.

Both are martial arts films with Zhang Ziyi in them. They each have really cool action scenes along with an engaging story.

Both are fantasy romance dramas in which a human falls in love with a supernatural character (played by Shin Min Ah in both dramas).

A teacher who cannot leave her students alone. The difference is that Misaki's ways to help her students are easily seen as helpful and caring while Queen's Classroom has more of a deeper and darker meaning.

Both has a girl with a terminal disease finding love. 1 Litre of Tears is more based on how the girl works through her sickness through her daily life and also finding love. Hidamari no Kanajo is more about the love relationship between the two and what it means to have a time limit on their relationship.

Both dramas about unification of North & South Korea and involve romance between a woman from north & man from south. Also has lots of action scenes