Recommendations

Both are adaptations from a manga that contained elements of time-travel. And amazingly enough, both also involved an incident set in Hokkaido while the protagonist was currently based in Tokyo. Also, both involved the protagonist being from a future with bad outcome ending up returning to the past to try to prevent incidents happening in order to change the past and future.

There is somewhat of a spoiler in this review for both dramas.
The only similarity is the twin aspect. I find the twins in both Arthdal Chronicles and Duel to be similar.

In Duel Sunghoon and Sungjoon are mere clones however, the two are very different. Saya in AC reminds me of Sunghoon so much. The two are both very stylish and the more well-kept compared to their twin-counterparts. Both of them are very eerie and are super smart. Both Sunghoon and Saya are evil but as a fan you'll find it very very hard to hate the both of them. Both twins are lonely and were mistreated as children.

Now we get to Sungjoon, he reminds me of AC's Eunseom (aka Saya's twin) because they both have a sense of doing what's best instead of their twin-counterparts. These two aren't entirely similar as Eunseom at the beginning and sometimes near the end is very naive this is due to how he grew up. Sungjoon too is naive but this is due to his memory not being fully there. Other than this you still find yourself routing for this twin as well.

The best historical drama. They take place in almost the same period and they have conflicts between the princes and political affairs. And in both the famale lead works in the palace for a time. And they are really sad.

Both are about catching criminals and have a detective with some sort of power, but in Higanbana; Keishichou Sosa Nana Ka?, she sees the memories of the crime scene rather than the memories of the person

It gives off the same feeling as Someday or oneday because one Female lead character seems bright and the other is little bit gloomy.If I explain more then I might give spoilers to you, so I'll stop here it's just that Female leads are pretty similar and the only difference is this one is a time travel and focuses more on that(Someday or One Day focuses on other things too but Switched is all about learning how to embrace yourselves and the consequences of body switch) but both shows low self-esteem part very well.Somehow both shows gives off the vibes about the inner beauty and how personality makes a person good not it's face/appearance.Although Switched is based on how people's appearances makes them treated differently whereas for Someday or One Day shows how someone's personality makes a difference!

Both movie have a bullied gay male main character, who comes across a dead body on a field. Things go kinda crazy

-Possession & Exorcism
-No Romance
-Very good special effects
-The Divine Fury has more action and fight scenes

The main characters are working as labor inspectors and the drama in general revolves around their profession through many cases the main leads encounter. Buuuut Special Inspector Jo deals with many other themes too while Dandarin Rodo Kijun Kantokukan is solely focusing on the work aspect

My Neighbor Charles showcases the daily lives of foreigners livingng, for the most part, long term in South Korea. Apart from singles, the show also features Korean-foreigner couples and families and their daily struggles.

It's exactly the same drama just filmed in China and it is more ignorant .. To tell the truth I saw it in many aspects, of course it's different, but I mean it is similar

The plots are completely different but these two shows carry the same vibe . Male lead is strong, wise and caring towrds the heroine . They are also star crossed lovers who keep getting separated from each other. Most of all the chemistry between the leads in both dramas is like no other and the female lead isn't afraid to show her love for the male lead.

Both have multiple LGBTQ characters and relationships, and both are fairly light with happy endings. Because of You has weaker writing and acting, but is still fun to watch.

Male lead falls in love with female lead in school age and is "devoted" to her since then.
Female lead plays an instrument.
Shy/reserved leads, slow burn romance.

They each deal with solving crimes and busting the bad guys. In both Signal and Lookout (Th Guardians) there are several main characters that work in a team and have very deep, heart-wrenching backstories and goes/focuses on each their individual stories equally in different segments of the drama. Sooji and Haeyoung have strong similarities regarding the crimes that changed and ruined their lives. The villains are especially vile and will make your blood boil in both, LOL.

While Lookout is not as superb as Signal (among my top faves!), I still strongly recommend it because it is good and have paces that will have you on the edge of your seat until the very end.

-Both female leads have similar personalities & life circumstances
-They involve family dynamics/children
-The mothers of the female leads are strong-spirited in both

They overall just have a similar feel to them!These are my top two dramas EVER & remind me of each other! Trust me and just watch them... ;)