Recommendations

Both take place mainly in apartment complex
Both have strong female leads
Both have an infection that is spreading for unknown reasons with little about it being told to them
Both have blood, strong special effects
People infected kill people whether that's zombies or monsters

I know this might sound weird, but the main serial killer in each one is hot...
Both trying to stop a serial killer, both live in apartment complex with the serial killer, both have blood/knives

Both couples keep their relationship a secret
Age Gap Relationship between Younger Male Lead/ Older Female Lead
Multiple couples, slice of life in each
Not too dark, easy fluffy romance
One night stand turns into romance with the main couple
Female lead is the boss to the younger male, he's below her in the workplace

Watching When the Devils Calls Your Name really reminded me of The One and Only. Even though the story/plot is different, both dramas include a romance between multiple main/support characters and trying to escape and find a distraction from the inescapable.

MC is given a second chance at life in a setting that's different / can be changed. MC is a part of the legal system (police officer/prosecutor) and knows more about the world he's moved to than the rest of the people around him.

Very good main leads, in both cases.

Similar starting point (keep in mind it's a regular trope in revenge stories), similar team-of-heroes story, though it'll definitely diverge (Rugal has super-powers, AML probably won't).

The forces of good are fighting the forces of evil, one of them will prevail in the end.

Romantic love story between ML & FL both shy & they are university student. Also A Korean exchange student come to their university & help them solve their love attraction, problem & overcome their shyness & awkwardness. Yamazaki Kento toooo adorable here.

Story about soldier. The settings both started with military training. They have a cold and stubborn hero that little by little learn to befriend and trust his comrades.

They have the same vibe even though the storyline is not the same. Also, one of them keeps bugging the other and pissing him off in a cute way.

If you liked watching Shining For One Thing, you can try watching Scripting Your Destiny. Though the two dramas have quite different plot and storyline, but both of them have some elements of fantasy and gives you the same vibe.
Both of these drams have the ML protecting FL without them knowing.
Moreover Scripting Your Destiny is a short drama, so it won't take you too much time to finish watching it.

Hope you enjoy watching!!

Both of these dramas are about celebrity life and the people around them. They show the people working in the industry and create a plotline given that premise. Both also feature a lot of cameos of famous personalities.

I was watching my gf is an alien after business proposal and realized some of the similarities like:
-Both male leads suffer from the rain and have a trauma linked to it
-Contract relationship between male and female leads
-Another male character likes the female (kind of a love triangle)
-Both males are rich CEO's and strong female leads works under them
-One male has a father while another has no parents
-The female lead helps solve the trauma (kind of)
-Happy endings
I think Business Proposal is more of a short, get-to-the-point than my gf is an alien.
Have a go, you might enjoy :)

tomorrow has a very similar feel to mystic pop-up bar.
both dramas follow a trio, both dramas are related to helping people's emotional troubles in a supernatural manner.
Female lead's goal in tomorrow is to help as many people through their memories to avoid getting sent to the underworld.
female lead's goal in mystic pop up bar is to resolve 100,000 grudes by entering their dreams to also avoid getting sent to hell.
All the characters in both tv shows are charming, and overall mystic pop-up bar is an enjoyable watch.

The similarity of the story is that they both FL has the ability to see spirits/ghosts. Both helps the wondering spirit’s to resolved and go back to their realm, but SYHH is more on a darker and serious side as for the MS are more towards ROM COM genre.

Romantic with obsession love story between FL a Japanese woman & ML a Korean man. This time is very rare to see collaboration movie/drama between other countries.