So far I like
Parasite
Business proposal
Thirty nine
I saw the devil
Train to Busan

What others would be recommended?

Pokémon.

sweet home

Oldboy
A Taxi Driver
Memoir of a Murderer
Memories of Murder
Burning
The Chaser
The Gangster, the Cop, the Devil

if you can find Spy Girl, it's dope. otherwise, check out Joint Security Area and the My Wife is a Gangster trilogy.

I watched The Chaser last evening and this was a masterpiece movie imo ! everything is inside, blood, violence, drama, some fun (with the cops^^). 4,5/5.

I gonna watch more for sure

If you like Gangster movies:
Bittersweet life
Dirty carnival
Rough cut (abusive actor that no one wants to work with, hires a real gangster to co-star in movie, gangster has 1 condition, real fight no fake stunt stuff)
New world (gang drama, departed/internal affair-like but not similar at all)
Man from nowhere
No mercy (mind fuck)

Mr vegenance trilogy (if you liked old boy, revenge type of movie)
My boss, my hero trilogy (if you liked my wife is a gangster comedy type of movie)

Hijacking your thread to ask about the Train to Busan sequel, anyone see it and is it worth the watch?

probably old Running Man

Nah it's trash