Kdrama_

Both dramas themed around life of idol industry in South Korea. The ML of Spring of Youth also acted as an idol in Namib. However his character in Namib was a jerk who manipulated people around Namib's ML with his fake innocent personality meanwhile his character in Spring of Youth is purely innocent person

If the secret romantic guesthouse was set in Joseon era, then Crushology 101 was set in modern era. Both dramas have similar theme of a young woman being approached by several handsome young men and she would be ended with one of them.

Both dramas have ML character abandoned by their siblings and forced to take good care of their nephew, and FL characters' conflict with theur family.

However in the Spring Fever, the nephew is no longer a baby but a teenager, and instead of being orphanized, the nephew was abandoned by his living single mother (ML''s sister). However, everytime seeing Our Universe, it reminds me of Spring Fever's ML when his nephew was a baby and he was forced to take good care of his nephew, and even in SF the ML must take good care of his nephew alone.

Spring Fever's ML and One the Woman's FL have physical strength much stronger than reguler human beings, and both characters' traits are developed by harsh situation they were forced to live in the past

Jung Seok (Park Eunbin) and Lee Woogyeom (Ryeoun) share some similarities with each other, since both characters are genious doctors who operate illegally without license. Both drama have similar theme, mainly talking about moral and ethics in medical field

Both dramas set in the pre-2000s era, in which Aema is set in 1980s while Undercover Miss Hong is set in 1990s. Both dramas present female characters working in male-dominated industries.

Both dramas are presenting harsh reality that are faced by women in the pasts. Like in Knight Flower, woman must dedicate her life to her husband even after his death. In Aema, woman may have career on her own but she must face male's domination, in this case like CEO Koo who is so exploitative toward his actresses

Both True Beauty and Namib explore how harsh Korean idol industry is. Idol industry in True Beauty is a side story but overall affects the characterization of both male leads. However, idol industry in Namib the center of the whole drama.

We need Han Seojun and Yoo Jinwoo (I mean Goo Jasung and Hong Siwoo, both are from 18 again kdrama) to have a collaboration please

Yoon Sang-hyun and Ryeoun were playing as father and son in 18 Again, this drama serves as their reunion.

Yoon Sang-hyun's characters in both dramas have anger issues and communication issues toward their own wives to the point their marriages are crumbling.

Both of Yoon Sang-hyun's onscreen sons in Namib (Shim Jinwoo) and 18 Again (Hong Siwoo - coincidentally was Ryeoun's character) has a lot of similarities like grew into timid boys with lack of confidence, seeing their parents fought every day, being bullied at school until other guys (Hong Daeyoung - whose older version was portrayed by Yoon Sang-hyun but the one who protected was Lee Do-hyun, the younger version but under name of Go Woo-young ; Yoo Jinwoo - portrayed by Ryeoun) protects them from their own bullies.

Namib, Twinkling Watermelon and 18 Again shows Ryeoun's strong bromance chemistry with his fellow male actors

Ryeoun seems playing similar character, like dealing with deaf character and musical aspiration. His interaction with his mom at this drama reminds me of his interaction with his dad in Twinkling Watermelon. His interaction with the other Jinwoo reminds me of his interaction with Yoon Chungah. But the most important is Ryeoun always have great chemistry with his fellow casts either male or female. However, Namib, along with Twinkling Watermelon and 18 Again shows Ryeoun's strong bromance chemistry with his fellow male actor

Both dramas are about a woman who lives with some men who are not part of her family, eventually creating bond with them and finally involved in romantic scenario with one of them

Same feel-good family themed drama with romance and friendship

If you watched another similar drama like FbC and TwM, titled 18 again, both MC of FbC and TwM was supporting actors of 18 again now are able to lead their own dramas