Recommendations

They have the same writers. They main character is also a twin in both dramas. There is a prophecy about the twin characters in the drama that is important to the plot. They also both have complex characters, meaning likeable villains, protagonists with a dark side, and characters which we won't understand at first if they're good or evil

Both are music dramas. Beethoven Virus was my first Korean drama, which display perfect Music Industry, love, friendship and struggles between 3 leads in an orchestra. DYLB also gives me similar vibes.

-bickering couple
-arranged marriage
-great chemistry between leads
Both shows give off a similar vibe where the stakes aren't too high but the romance is strong!

The similarities are
rich famous male lead
Hate to love relationship
Tsundere personality of male lead
A Scene where leads are lost in a snowy place

It's the side story from The Lost Tomb like Reunion. The timeline is 2 years before reunion. It's more focus on the nine families and ofc, we still can see Wu Xie.

These 2 chinese rom-com has fake marriages between tough and martial arts trained princes ML and funny, smart witty FL.

These shows are kinda similar because in the happiest moments of their life they thought that was going to be their "happy ever after" but as years go by they get divorced. And then unexpectedly go to their youth.

The show invited seven girl group members to create their very own Korean drama series by becoming accredited scriptwriters as well as acting in the series as fictional versions of themselves. And able to perform on music shows as well.

same concept, added a few new cast like GOT7 JACKSON, KARA YOUNGJI.
this show is to make new relationship with others celebrities of making new friends, getting know each other.

Older male lead becomes young
Tries to develop a relationship with his son (and his daughter in 18 Again)
The difference is that the romance is between his wife in 18 Again whilst Mr Back is with an employee at his company

They both have college romance and very less negative roles. If you liked accidentally in love then you will like Love O2O for sure.

Both female leads undergo plastic surgery and a major appearance change. Diamond lover is more workplace/adult drama. As where Gangnam beauty is more college drama relating to image and status.

It's the prequel to part 2. Both are short and hilarious, I recommend watching part 1 if you want to understand the flashbacks but you would still understand the drama if don't want to. They got a lot of same actors from the first season which is always a plus.

both deal with ghost, however this is about a detective and a woman who does anything in her power to not see any ghosts

The similitudes in these shows is that they revolve around cheating.
Otherwise, while Plerng Boon has much more production value (quality of the show, acting, screenplay...) as a Ch3 product and the story is more "complex" Talay Prae is of a lesser quality overall.

Another difference is that the motivation of of the cheating partner and their characterization are world apart.