@Lifunia

-Black & White
-Fated to Love You
-Two Fathers
-It Started with a Kiss
-My Lucky Star
-Sunny Happiness
-Autumn's Concerto
-Goong
-History of the Salaryman
-Ho Goo's Love
-A Gentleman's Dignity
-49 Days
-Cinderella Man
-City Hunter
-Miracle in Cell No.7
-Miss Granny
-Shark
-Shining Inheritance
-Sungkyunkwan Scandal
-The Bridal Mask
-Prince of Lan Ling
-Drama Go Go Go
-Back to 20
-Bloody Monday
-Rich Man, Poor Woman
-Doctor X
-Itazura na Kiss
-Itazura na Kiss- Love in Tokyo 2
-Kazoku Game
-Bitter Blood
-Mother
-LIAR GAME
-1 Litre of Tears
wow you've watched soooo many dramas, it was hard for me to find one you hadn't watched yet!

so here's a drama I unfortunately haven't seen yet, but that I intend to watch very soon: Flowers for my Life

I read it's an underrated drama that is unusual and insightful. It's set in a funeral home, with a tone that can be sad, humoristic or dark.
@Kim-Park-Lee

1 Litre of tears
Boku no Ita Jikan
Byakuyako
Kyou wa Kaisha Yasumimasu
Pinocchio
School 2013
Secret Love Affair
White Christmas
@Toots 
Most of the dramas and movies on your list I haven't seen (and now I'll be adding more to my list)... However,
You're All Surrounded - Currently my favorite drama.
My P.S. Partner - this movie is probably near the top of my favorite rom-com movies.
Ouran High School Host Club The Movie - really cute, liked it about as much as the drama. (And it was nice that it incorporated things from the manga, which didn't get a chance to be in the anime.) 
@Levee 
The Bridal Mask - It has everything. Powerful story, action, romance etc... It's so intense throughout the drama. There won't be any boring moments. :) 
Bad Gyus - It's good, nice fresh story. 
@Nina

I Hear Your Voice is one of my all time favorite dramas and I am fairly picky, but everyone should see it, the story is fabulous.
Sungkyunkwan Scandal - If you want something with good bromance and comedy. 
Dream High - if you want something cutesy with lots of good music and dancing. 
Time Between Dog and Wolf OR Iljimae - If you're looking for something a little more action packed.
@Starae

From your list I'd recommend:

Kill Me, Heal Me
The beginning of episode 1 is a bit strange, with some really cringe-worthy English, but once you get through that, it's an absolutely amazing drama.  A word of warning, though... watch it when you have plenty of free time.  It's one of those dramas where you'll be saying to yourself, "Just one more, just one more..."  :P  Oh, and you might want to keep some tissues handy.  There's a lot of emotional, tearjerker moments.  :)

A Werewolf Boy
I wasn't really expecting much when I started this one.  I'm a huge vampire/werewolf fan, so I've seen (and read) a LOT with those themes, and I was prepared for this one to be an average "just to kill some time" movie.  Boy, was I wrong.  I really, really loved it, and thought it was quite unique.  If you're a paranormal/werewolf fan, I highly recommend it.  :)  It's also very emotional, so you may want to keep some tissues on hand for this one as well.

Bloody Monday
It's been several years since I've seen this one, but I remember enjoying it very much.  It's one of those "edge of your seat, must watch another, and another..." dramas.  My husband and I watched this one together, and he loved it as well.  IMO, season 2 wasn't quite as good as season 1, but it was still very enjoyable and definitely worth watching if you like season 1.  :)
@Neyjour

Out of the ones that I've seen on your list, I'd recommend:

Ghost
I have a soft spot for thrillers, and this drama really provides in that department. However, if you're looking for a romance, this lacks in that area.

Mirai Nikki
Better than the manga in my opinion. I love that the writers changed it around, and made it their own. A great twist, and a nice message.

This Is My Dad
Nothing thrilling about this special of course, but it's nice if you're looking for something heart warming.

No Breathing
Again, if you're looking for something heart-warming this is nice as well. Another plus if you're a Lee Jong Suk and/or Seo In Guk fan.

Young Hot Bloods
This movie is a bit on the slow side but it definitely has that nostalgic feeling. Again, since I'm a Lee Jong Suk fan that's a big plus as well. It was also nice to see Kim Young Kwang since they were in Pinocchio together. They were part of a love triangle in this one as well.

@SmileHoney

Based off of your PTW list I recommend:

Cunning Single Lady- Comedic love-hate relationship with surprising depth. If you like this check out "Lie to Me" as well, both are similar and very good.
Bride of the Century- If you are looking for a romance drama this has it all, bad in laws, love-hate relationships, and cute banter.

Based off of your top ten I also recommend:

Pinocchio- Lee Jong Suk is in this as well as I Hear Your Voice, which you enjoyed. Also, they are both masterpieces. 
Shut Up Flower Boy Band- Because you liked Monster, they are both about trying to get through high school, win a competition, and be part of a band.

Happy Drama Watching!


*for whoever recommends for me, please also look outside my PTW list, I really am struggling to find a new drama!
@Azzuritis
LIAR GAME! - y favorite japanese drama
Nine: Nine Times Travel - i came to like Lee Jin Wook coz of this
What's Up - i really believe this drama is underrated
@prettytin
Flower Grandpa Investigation Unit!!
@versaillesyoo I highly recommend City Hunter! While it's not perfect, the sum is much better than the parts and is a really enjoyable watch with a bit of everything (without seeming messy). Good writing, great cinematography and tone, a great cast, and a great score to boot!
@Mari

I would recommend Bad Guys. It's from OCN and it's not the typical crime investigation show. I think it's one of the best dramas from 2014 and it's definitely not overrated. 

Besides that one above I'll just list some dramas I recommend and a short reason why. You can trust me as I've seen over 400 dramas :)

Boys Over Flowers - It's a legendary drama that everyone should watch no matter how good or bad it might be....
Can You Hear My Heart - A total masterpiece when it comes to plot and cast. Everything is perfect in this drama.
Coffee Prince - Another must-watch drama for every dramawatcher.
Devil Beside You - When it comes to taiwanese dramas I believe this one is "the one" that we all should know. It's really good !
Good Doctor - I'm repeating myself but this one is another masterpiece ~ 
Liar Game (KorVer) - It's pretty different from the original Japanese version but I think this one was better for some reason. 
Smile, You - If you are a fan of warm family dramas I would recommend this :) It's currently the longest drama I've finished. 
@HAVA-RAVA

-Autumn's Concerto - One of the best dramas.
-Black & White - One of my favorite dramas involving cops.
-Love in Disguise - Loved it.
-Down With Love - Tomboy + rich guy love.
-Fated to Love You - It's better than the Korean version in my opinion.
-Sunny Happiness - Loved this one.
-Smiling Pasta - This one cute drama.
-Rock 'n' Road - One of my favorite music-related dramas.
-In Time With You - Really good.
-Wuri's Family - One of my favorite classic Korean dramas.
-The Chaser - Not bad of a drama.
-That Fool - One of my favorites.
-Shark - Loved this from beginning till end...expect the ending.
-Angry Mom - This one awesome drama right now.
-Marriage, Not Dating - Funny as hell!
-Scarlet Heart - Must watch!
-The Little Fairy - Loved this one!
-Let's Go Watch Meteor Shower - Zheng Shuang and Zhang Han's chemistry was awesome but this version of BOF isn't that good.
-Mulan - One of the best Chinese movies.
-Legal High - Funny and the guy speaks so damn fast.
-L: Change the World - Death Note is the best ever!
-Kuroshitsuji - Not bad.
-Hanzawa Naoki - Awesome bank/debt collection-related drama.
-Death Note - One of the best adaptions from a manga.
-Dear Sister - Definitely one of my top dramas.
-Bitter Blood - You'll enjoy it if you like cops and comedy mixed together.
-Black President - I enjoyed this one.
@Plural

Wow, you have a really long PTW list!
My recommendations: The King of Dramas, Ashita Mama ga Inai, Pride, Gap Dong, After School Lucky or Not and Yamato Nadeshiko Shichi Henge.