Recommendations

Both drama is about a female lead go to comic world and meet his ideal boyfriend there. However in W, female lead is real human being, meanwhile male lead is a comic character.
In Lost Romance, both male and female leads are human being in the first place, they are just accidentally go inside a comic book, because both in comma state. So it's more like their real body still remain in the reality, it just their spirits move to the comic story.

In W (korean drama), the story is more like magical from the beginning. If you are looking something more fantasy with super villain and heroic actions, also teleport things between real world and comic world, then just go watch W drama. But if you are looking for a story that focus more to romance, then watch Lost Romance (taiwanese drama).

Both are about relationship among sisters. They both have something to do with their father's death.

Both have different story-lines but there are some similarities in them.

Both are slap-kiss romances where the ML is extremely in love and possessive of FL.

Both lakhorns have the boss-secretary trope. In both lakhorns FL has a second lead being smitten with her and visiting her on after work hours to have lunch with her,which ML hates.

In both lakhorns ML is very drawn to FL and does everything to be near her.

In both lakhorns ML has a niece he adores.

Both of them have messy rich people drama. The main female leads are strong.

A country girl that moves to the city, and a guy who first doesn't like her falls in love
Beautiful and heartwarming refreshing dramas

When you watch these dramas you should know you are in for a
Cruel ride
Painful romance
Rough life
Great music that digs deeper into your wound

So prepare your hearts

BL dramas. The cinematography is great in both, when watching Life on the line I was reminded immediately of Dark Blue and Moonlight. Also, in some part of the story one of the leads keeps looking for the other after they separate. The way they approach LGBT themes is similar.

Both are slower-paced, romance-focused stories set in small towns with a strong emphasis on establishing and developing characters within the tiny communities. The side characters add depth to the plot, but also get interesting storylines on their own.

The dramas have similar humor and a cute couple even though the guys in Boy Next Door are not together.

Very similar drama: 3 main characters, 1 is a devoted mother, 1 is young and lost in life, there's a cheating scandal, some entrepreneurship, an insight into a rural Chinese hometown
Nothing But Thirty is my favorite of all CDramas ever made, and To Dear Myself is the most similar drama that I've found

Twin sisters
Impersonation
Accident
Male lead gets confused with identity and then tries to keep it a secret

Geu Roo and Jin Tae are both special kids who have to get used to new circumstances due to sudden changes in their lives. Sang Goo and Jo Ha both have boxer backgrounds. They are both cold and rude at first but change while they are learning to take care of someone else besides themselves.

Both productions are set in the same "universe" with Guan Hong Feng (ML in Day and Night) being a supporting/guest character in Reborn.

Lives of male leads in both productions get changed due to movies during the tumultuous period in communist China.

Both productions star Zhang Yi as ML who befriends a teenage girl he once had an enemy-like relationship with.