If you liked the first season, you'll definitely find the second season to be a shift in tone, but for the better. Tale of the Nine-Tailed 1938 balances humor with serious tones very well, and focuses more on bromance than romance.

They're both about a love story that evolves in a book publishing company. In both dramas, the male lead uses the quote from Japanese author Natsume Soseki about the moon being beautiful to express his love for the female lead. I think Moonlight took heavy inspiration from Romance is a Bonus Book - a lot of the side plot threads are similar as well.

The girl from the real world wakes up in the world of a novel, and falls in love with the male protagonist. W is much more action-packed, but Lost Romance has some great comedy, a dreamy second male lead, and some hot and sexy moments between the main leads.

Both dramas are rom-coms, and both have an outgoing female lead who initially gives the main lead a bad impression.
Unpopular opinion, but I think the Undateables is actually a better drama overall.

In both dramas the main leads start off on the wrong foot, with the male lead getting the wrong impression about the girl and then slowly falling for her despite himself. Also in both dramas, the male leads are newscasters.

The plots to both these dramas is very similar - the little guy sticking it to the corrupt big guys. Plus they're both over-the-top, feel good comedies.

Both Tunnel and Vampire Prosecutor are investigative crime dramas. They both have intense cases each episode, and also a good sense of humor and camaraderie between the investigation teams.

Extraordinary You and W share a similar theme in cartoon characters becoming self-aware, and trying to change their fate.