What are some of you all time favorite dramas without romance? I am going through a not in the mood for romance phase right now and would love some recs. My absolute favorites that I have seen: Sweet Home, Kingdom seasons 1 and 2 (just finished both seasons and I LOVED it), The Uncanny Encounter, Train, and School Nurse Files (I guess there's a hint of romance in the last two but not much). I am more in the mood for sci-fi, thriller, action, fantasy type dramas as opposed to slice of life dramas. Dropped All of Us Are Dead and Happiness and saving Squid Game to watch with my friend. Thank you ahead of time!

I looked to my wachlist and found, that from korean dramas I mostly watched only those with romance. But I found few with no romance:

Nightmare Teacher - this is quite good mystery horror
The Guardians - this is also good action, thriller, crime drama

But my favourites would be rather these japanese dramas:
Hello Harinezumi - mystery comedy. It has romance, but it is not main focus
Limit - thriller, survival, psychological
The Werewolf Game: The Beast Side - this is not drama, but series of 8 movies, this one is 2nd in that series and I like it the most. It is about a death game.

And then some others, but they are mostly only comedies or romcoms.

Suika - It's a slice-of-life drama with no romance.  It's about 4 women who live together in a boarding house.

Edit: Sorry, I didn't notice that this was the K-drama forum.  I hope you don't mind a J-drama recommendation.

The Cursed (horror, thriller)

If you don't mind older dramas:

Have you watched Sell Your Haunted House? It was one of my favourite k-dramas of 2021. Narrative stayed pretty tight throughout, the leads had more of a sibling/bff/buddy cop energy, and it has a strong supporting cast. Plus, it was pretty refreshing to see Jang Nara play a completely different character to normal.

Inspector Koo, 

Watcher, 

Signal and 

Move to Heaven 

are my top favorite dramas without romance. Though only Signal can be seen as a suoernatural drama. 

Designated Survivor: 60 Days    (political action thriller)

Vagabond    (action thriller)

The Veil and Law School

 ArniA:

Designated Survivor: 60 Days    (political action thriller)

Vagabond    (action thriller)

i second ArniA's recommendations above. Designated Survivor: 60 days is a SKorean remake of an American series, and many said it was a better series. Vagabond is a netflix original kdrama with Hollywood stunts, and a very gripping plot.

you might additionally check out  one of these...

prison playbook
argon
children of nobody
d.p.
defendant
falsify
hot stove league
jirisan
juvenile justice
kill heel
life
misaeng
mother
nobody knows
one ordinary day
secret boutique
stranger
tell me what you saw
the devil judge
the silent sea
through the darkness

Stranger and Lookout