Recommendations

Both are sweet mini stories of lesbian romance in a school setting, where the protagonist develops feelings for her best friend.

About the people who do business and people who actually love their jobs.
Cho Seung woo character is similar to that of Bae in Hotelier.

Both have a similar first half where a plant fairy, who does not understand what love is, makes a high ranked deity fall in love with herself. After that both series get more serious, but Ashes of Love gets a hundred times more serious and angst heavy, while Dear Herbal Lord stays quite light all the way through.

They both show the DPRK and ROK people working together to save the peninsula (in totally different ways).

Revenge plot, hidden identity, struggle of FL to find her place. CC is darker (#melodrama and NOT as pleasant an ending) than HJS but they both have this edgy tone that keeps you tilting on the edge wondering what will happen next.

Both are light, easy to watch dramas. They both have people teaming up to do detective work in ancient times.

Both dramas consist of world where human and ghost exist.
The male leads find themselves crossing the line between the human world and ghost world, helping the lost souls to find peace before they can go off to a better place. They're both fantasy filled with trilling events.

Both dramas have a time travel aspect and I feel like the reason as to why they time travel are very similar. *SPOILER ALERT* I wouldn't necessarily say this is a spoiler but, you know, just to be sure. I feel like the reason the characters in both dramas are experiencing time traveling is because it will help them realize what they value most in life and pursue it.
Both dramas are also focused on job occupations (though one is about doctors and the other is about police officers).

They have a similar kind of humor (though The Fiery Priest is more often and more exaggerated in use). Kim Nam Gil is the lead in both the dramas too but that's practically the only similarities.

orchestra them dramas
i personally didn't like IWHYS and i'm sure park eunbi won't disappoint me as always

they have the same vibe of performance ballet/ orchestra

Both are using this technique where characters are talking in front a camera, a nice technique to show where these characters are coming from. Sixteen and River's edge are both teen angst driven, the latter is just more messy, has older set of characters, and better acted.

Both involve detectives and time travelling. The mystery unfolds slowly, while keeping the audience on the edge of their seat with each episode. Parallel worlds infused in science-fiction and the genres of crime and thriller. If you liked Signal, you might greatly enjoy Alice.

The tone and the ill-fated relationship between the characters due to their intertwined pasts. Even though totally different setting and plot, both are heartbreaking dramas that will leave a long-lasting impression and still hurt when thinking about them long after one has finished watching them.

Both dramas deals with a divorced couple getting back together, both work in the same workplace and also have Lee Min Jung starring.