Both have a very similar feel to them. In train the ml travels to an alternate dimension in order to solve a serial murder case. And in Kairos the ml gets in contact with a woman from the past in order to save his kidnapped daughter. Though the storylines are different, they both use fantastical elements to solve a crime.

In Lucky Romance the fl is convinced she brings bad luck to people and wants to stay away from others/the people she cares about as a result.

In I'm not a Robot the ml believes he is allergic to people and has built his entire life around never touching another human being.

Though these are obviously different, I found the concepts similar and the general feeling when watching was also quite alike. Both romances are very cutesy and brings a smile to your face.

Both dramas are about rescuing a child.
Both have similar vibes.
Both are dramas that made me cry buckets.
Both are fucking fantastic!!!!!

Both deals with abuse and the flaws of the legal koren legal system. Also the vibe is quite similar I think. I personally found Mother to have more light-hearted moments.

Both deal with magical realism. In You who came from the stars the main lead is an alien, and in Secret garden the main characters switch bodies. In ywcfts the mfl is an actress and in sg the mfl is a stunt woman. Both dramas have a similar vibe.

They have a similar vibe. The same main actress and although the extraordinary creature in Legend of the Blue Sea is the woman and not the man Jun Jihyun plays a somewhat similar role in both. Both are light hearted and fun.