Both are Chinese dramas set in college, Love O2O is e-sport romance drama and To Fly With You is sport romance drama. I think both have similar vibes, give same wonderful feels. Sweet romance of lead couples will give you butterflies.

Both are modern c-dramas which Bai Lu acts as female leads. Her characters are strong and elegant ladies. Both dramas have amazing on-screen chemistry between leads and excellent acting performances.

Both are historical dramas starring Bai Lu as female lead character. Bai Lu's characters in both are very different from each other.
In One and Only, the leads have a Master and Disciple relationship, she calls him "Shifu". Also in the Legends, FL sometimes calls ML "Shifu" while she is pretending to be someone to get close to him.

These two dramas are Chinese historical fantasy dramas. ALP has main characters as Gods and a lot of supporting characters are immortals too. The Castle in the sky has ML as an immortal.
Both have - sad but beautiful romance, great chemistry between leads.

I noticed that these two have similar vibes.
- both female leads are doctors who worked hard from the bottom.
- in Forest, male lead is sort of a rescue officer, while in You Are My Hero, male lead is a special police who often rescues people in need.
The leads's chemistry and acting are very good in both dramas.

Both have a modern person travelled through time to historical era, and involved in a sweet love story with main guys who are both smart and resourceful.

I just realized these two dramas have similar vibes.
- Both are time-travel sageuk dramas
- Joseon Dynasty
- Beautiful Love Story and amazing lead couple
- Both male leads are tricked by second female leads and they thought SFLs are their childhood first loves but actually FLs are.

The same thing between these two dramas is that a man's soul is entering into a woman's body. Both seems fun and hilarious.

Both are South Korean dramas, similar in that it features a modern person who time-travelled to the past. In Moon lovers, it is Goryeo Dynasty. In Mr Queen, it is Joseon Dynasty. Another difference is that Mr Queen features a man in a woman's body and Moon lovers was a girl residing in another girl's body.

These two dramas have similar complexity based on different concepts. Parallel worlds and thriller mystery are involved in both dramas.

Both drama, set in historical period, have a beautiful and interesting plot based on the power struggle.
The female protagonists are both strong, smart and skillful. 
Both drama have a lot of episodes but they are very exiting and not boring.
Princess Wei Young are better in costumes clothing.

The storylines are very similar, how a woman's journey to become the most important female figure (Queen) of a country. The South Korean Drama has one female lead and two male lead, just like this one.