Black .. it's a Fantasy/Supernatural Thriller with a bit of romance it's a really good one if you like something with suspense and mystery plus some comedy mixed in.
Prison playbook. Its a really good sort of slice of life series with comedy and drama with a warm atmosphere to it & one of my personal favourites.
A Korean Odyssey this one's definitely supernatural through and through. Its like a modern day fairytale about ghosts/demons and fairies with romance... a really cute drama.
Romantic-comedies I suggest:
Descendants of the sun (Soldier x Doctor romance)
Emergency couple (Medical Romance)
Cunning single lady
Oh my venus
You who came from the stars (Supernatural)
Strong woman Do Bong soo (Superpower)
Big (although has quite some flaws but nonetheless very cute scenes and is also fantasy) one of my first kdramas
Goblin (Not a fan tbh but it is definitely loved by so many and has been a craze for most kdrama fans so you might like it.. also supernatural/fantasy)
More serious Romantic-Melodramas
That winter the wind Blows
On the way to the airport
Disaster movies (I know they aren't series but I think they can get you more interested in korean cinema and korean tv in general)
Train to Busan
Flu
Pandora
As for Comedy I suggest you start watching Variety Shows because they're flat out HILARIOUS! Whenever I'm bored or feeling down I just put on a variety show that I like and I'm instantly happy and laughing my lungs out.
Hope I helped, and welcome to world of korean dramas! :)