Korean Drama OSTs You Love

Heartstrings - Jung Yong Hwa (Heartstrings)
Even if it's not necessary - FTISLAND (Heartstrings)
Because I miss you (Band ver.) - Jung Yong Hwa
The Woman - Baek Ji Young (Secret Garden)
Star - Kang Minhyuk (Heartstrings)
Promise - A.N.Jell (You're Beautiful)
A Litte Bit More - Sweden Laundry (Cheese In The Trap)
One More Time - Kim Hyun Joong (Playful Kiss)
Because I'm Stupid (Acoustic ver.) - Kim Hyun Joong (Boys Over Flowers)
Stand By Me - SHINee (Boys Over Flowers)
You&I - Kim Jong Wan (Weightlifting Fairy Kim Bok Joo)
+ All the amazing "Shut Up Flower Boy Band" songs 

I've been listening to the Goblin OST like crazy, 

I also love to like to some of the stuff from Uncontrollably Fond.

I like City Hunter and Faith a lot too. 

Auditory Hallucinatons - Jang Jae In  from Kill Me, Heal Me 

Goblin's OSTs are 95% heartbreaking to hear.

Healer

Lee Sung Yeol - Fly (Incomplete Life)
Ryu Ji Hyun - X-Out (Please Come Back Mister)
Jannabi - Wonderful (Dear My Friends)
Bolbbalgan4  - Dream (Hwarang)
Heize - Round and round (Goblin)
Im Sun Hae - Will Be Back (Scarlet Heart: Ryeo)
Kim Hyung Joong - 너에게 퐁당 (Splash Splash Love)

Ben ; Stay. (oh my ghost)
Ali ; I love you, I'm sorry. (angry mom)
Sumin ; U&I. (bring it on, ghost)
Tiger JK ft Jinsil ; Reset. (school 2015)
Wendy ft Yuk Ji Dam ; Return. (school 2015)

Stay With Me - Chanyeol & Punch (Goblin)
If - Taeyeon (Hong GIl Dong)
Can You Hear Me - Taeyeon (Beethoven Virus)
Because I'm a Girl - IU (Road Number One)
Reset - Tiger JK (School 2015)
Suddenly - Kim Bokyung (City Hunter)

And although I didn't finish watching Boys Over Flower, that series has a whole bunch of amazing OSTs.

Tiger Moth (Acoustic) - Monsta X (Shopping King Louis)
Flower - Seo In Guk (Tomorrow With You)
Like A Dream - Ben (Another Miss Oh)
My Destiny - Lyn (My Love From Another Star)
My Time Towards You - Alex (Bubblegum)
Who Are You - Sam Kim (Goblin)
Hope Its Not A Dream - Lee Young Hoon (Falling For Innocence)