I'm recommending you The Prison eventhough it's a movie. In my opinion it was a nice prison tale and had a grandiouse finale.

Page Turner and School 2015

@Songyi this isn't on your PTW list, but you should totally check out Witch's Court (currently airing). It's  unique and exciting. ;-)

BLACK - Very Nice Grim Reaper Story and Song Seung Heon is doing a great job.

GO BACK SPOUSES/COUPLE (Confession Couple) - My fave in all drama airing right now. If you're a married couple you will appreciate the story cause you can relate. The story and the cast is amazing. It will make you laugh and cry at the same time. The story is more realistic. If you suddenly wake up and you're back in you're 20 y.o self what will you do? Are you going to change all of it? 

While You were sleeping - Great drama. Nice story and magical OST

Jealousy Incarnate - Gong Hyo Jin and Jong Jeong Seuk are really awesome in this drama. One of the drama that I really recommend.

Goblin - One of the best drama of 2016-2017

SIGNAL - Underrated drama but really one of the best and perfect drama. Story and the cast. No romance but it was really good. 

TUNNEL - Choi jin hyuk and Yoon Hyun min's bromance. Plus the past to present time travel is great.

CINDERELLA AND the 4 Knights - A bit like boys over flowers . A feel good drama. Handsome Jung il woo

Nice to see the idea I started 5 years ago is still alive.


Singles Villa. 

Hanzawa Naoki is a must watch.

Circle

 Black

ETA: I also recommend Mad Dog (though it's not on your list)

@ Rin .. I recommend Hanzawa Naoki and Love Shuffle ...  :D