There's a similar theme of former gangsters attempting to run a legitimate business and leave their life of crime. Both dramas have kind of a found family situation going one.
If you liked the first few episodes of Heartbeat, and the overall vibe initially, then you will like From Now On, Showtime. Heartbeat's strength was likeable characters, good acting and a great concept. But the writing was unable to fully flesh out the drama in the way that it deserved. From Now On Showtime has the character development, the acting, the concept and the writing is so well done. It delivers in ways that Heartbeat wishes it could have.
Both dramas are about fictional characters that become self aware. Both dramas are quirky and romantic.
Psychopath Diary is a dark comedy. If you like this drama, and you like dark comedies, you'll probably like Feel Good To Die. It's about a woman who is stuck in a Groundhog's Day like loop and has to save her boss from dying in order escape the loop. The best thing is the comedic ways that they kill off the boss. It's hilarious.
They're both about characters that are dealing with modern relationships while navigating adulthood and careers.
Both dramas are about a man and a woman living together and navigating the relationship that forms from proximity. I prefer Because this is My First Life, but Personal Taste is worth watching
There's random elements that are similar. Both dramas have female leads that like to play hide and seek when drunk. They also both have a name game to verify compatibility between characters. The pace is also somewhat similar. I prefer Eulachacha Waikiki, but Beautiful Gong Shim is good too.
The main male leads both have a slightly sordid history. Ahn Dae Tae in Beautiful Gong Shim has a similar personality to Hedgehog in Panda and Hedgehog.
Both dramas involve a group of people living together. They're both funny and have great group dynamics. Go Go Waikiki is more nuanced and complex. Surplus Princess is fun and entertaining.
Go Go Waikiki is definitely funnier, but both dramas are about people doing their best to be successful in their own terms.
Both have characters that are navigating balancing modern young adulthood and managing society's and parental traditional expectations. Both dramas are funny and the characters are well developed.