Battle Royale which is the only movie/drama from your PlanToWatch list i have watched .
I think you should watch Bloody Monday (Japanese Thriller/Crime/Mystery) that fits your preference 
bad guys
God's quiz
I remember you - great cast, acting
It's okay that's love  -> if you like romcom, psych too
My GF is a Gumiho -> cute romcom
@Spring 

I am going to recommend. . . .  
Cruel City
Two Weeks
Gap Dong 

Mystery/ action/ psychological  ... which based on your PTW and your profile I would say are right up your alley ^^
There are so many that i would recommend, but I'll keep it at the top 15. Hopefully that's not too overwhelming :)
From you PTW list i would recommend the following: 

1 Litre of Tears- Boku No Ita Jikan Both are similar and very good watches.
Angry Mom
Autumn's Concerto
Bad Guys
Can You Hear My Heart
Cheer Up!
Dok Ruk Rim Tang- Although it might be difficult to find all the episodes 
Gu family Book
Healer
Kimi Ni Todoke 
School 2013
That Winter, The Wind Blows
Vampire Prosecutor 2
Witch's Romance
You're All Surrounded
Bad Boys
Im a cyborg but thats okay
Ouroboros
The Memorandum of Kyoko Okitegami
Tough as iron
Very Ordinary couple
I reccomend you to watch
Mother 
Nobody Knows
and there are so many other good dramas you might like

Healer
itazura na kiss 1 & 2 (the japanese version 2014)

So many to choose from! I'll keep it to 10. But definitely: 

Battle of Changsha
A gentleman's Dignity
Warrior Baek Dong Soo
Iljimae 
Empress Ki
Cruel City
Rich man, poor woman
Secret
Love me if you dare (although it's still airing)
That winter, the wind blows

They are all my favorites! :)
Confession of Murder
Dr. Frost - if you like light mystery and psychological ones
Liar Game 
Missing Noir M
The Crucible - one of the best Kmovies, well that's my opinion


Btw, let's wait for Remember! :)
Hwayi: A Monster Boy
Incomplete Life
Two Weeks

I'm also going to recommend Innocent Man, cause it's my all time fav and it's not on your list ;)
Dramas that really surprised me and would highly watch are:

HOTEL KING
MASK
BAD LOVE

all above are a must to watch!  If you want a great family drama, although long but all worth it watch WHAT HAPPENS TO MY FAMILY? ... it will also be a drama that you will enjoy!

Older dramas that are must:
SCENT OF A WOMAN
THAT WINTER THE WIND BLOWS
INNOCENT MAN
LIE TO ME
LIAR GAME
THE MASTER'S SUN
SECRET or SECRET LOVE with Ji Sung
CITY HUNTER
A GENTLEMAN'S DIGNITY
MARRIAGE NOT DATING 
PROSECUTOR PRINCESS
PROTECT THE BOSS
CAN YOU HEAR MY HEART?
I MISS YOU or MISSING YOU
HEART TO HEART
BOSS AND ME
STAIRWAY TO HEAVEN
STARS FALLING FROM THE SKY
YOU WHO CAME FROM THE STARS
PERSONAL TASTE
....  and I am sure many more already mentioned. 
@mariola you list has literally 4 dramas listed, all sections combined, and i guess i'll pick history of a salaryman because it's a light, crazy, comedic and a basically enjoyable watch without much insensible melodrama or such. From what I've heard, it's a lot of fun to watch. ;D
@Bipasha

I would recommend the following:

Cheer Up! ... really funny, but also with dramatic elements. It has very loveably (and also hateable) characters and really good friendship and love relationships. The love story between the male and female lead is really cute, but not mushy. There is also an epic bromance going on. There is no boring episode and I always wanted to know what would happen next.


@Archania
I recommend you to watch Goong as well as I Remember You. I will admit I'm a bit biased towards Goong, but I truly believe it's a good 'classic' drama. Even though there's drama, it generally makes you feel good a lot and fall in love with the main characters. Not only that, but the family of the female main char is super adorable and memorable :)
I remember you has great bromance (I'm still watching it though). I'd mainly recommend it if you like psychological stuff. There's subtle romance as well, but I would say it's not the main focus. Also, there are quite a lot of twists and turns in the beginning. As confusing as it is, stick with it because later on things will be quite obvious, yet still super enjoyable because you want to know how it'll all end (up for everyone). Never a dull moment imo
Your list suggests that you seem to like romance. I would recommend first finishing I Hear Your Voice, and then starting City Hunter. It's a great drama with the right balance of action, adventure, thriller and of course drama. The romance between the main leads is also really well played out, and the chemistry was probably helped by the fact that the actors were actually dating when they shot the series.