Old: All About Eve, Aja Geum Soon, Smile You, Attic Cat, Full House

Recent: Boss and Me 
Secret Garden
Coffee Prince
Pinocchio
Doctors
Descendants of the Sun
Weightlifting Fairy Kim Bok Jo
Love 020
Heirs
You're Beautiful
Boys over Flowers
Hyde,Jeckyll, Me
Orange Marmalade
Meteor Garden 
Secret Garden
Coffee Prince
Time bw Dog and Wolf
Reply '97
Innocent Man
DOTS
Secret
Kill Me Heal Me
Healer
Fated to Love You
Goblin
When a Man's in Love
Oh My Venus
Marry Me or Not

 
Flower Boy Next Door 
Heartstrings 
Boss & Me

I typically don't rewatch dramas. I'll rewatch an episode or scenes that I loved when I find myself thinking of a particular drama or ship. 
The only drama I've rewatched was DOTS (it was my first drama as well)

Autumn in my Heart - my first korean drama, so I'm bound to re watch it a couple times over for the sake of nostalgic and melodrama.
Soulmate - Sometimes I just want to watch a particular scene, but I end up re-watching the whole drama again lol.
Heartless city
healer 
DOTS 
Innocent Man
Descendants of the sun
Emergency Couple
Masters sun
the princess' man
secret garden
devil beside you
mars!
secret
midnight fm ( its actually a korean movie but i have rewatched it 3 times!)
autumn concerto
MOSTLY I JUST WATCH MY FAVORITE SCENE. Not really watch a whole full drama. skip skip skip
1 Princess hours
2. Sassy Girl chun hyang
3 wonderful lif
4 bbf
5 marriage not dating
6 descendant of the sun
7 autumn concerto
8 itazura na kiss
9 another miss oh
10 romantic doctor kim
11 another miss oh
12 discovery romance
13 boss and me
14 can we get married
15 emergency couple
16 it started with a kiss
17Jealousy Incarnate
18 just you
19 love o2o
20 my sunshine
21 something about 1%
22 the king of drama
23 the moon that embraces the sun
24 when a snails fall in love

Go Ho's Starry Night
Sly and Single Again
Marriage Not Dating
Triangle  kdrama
Liar Game kdrama
Not a rewatched but, 
Master's sun 
coffee prince 
Eternal love!!! This is so good, I tried to resist and watch it after a month but it was too hard so I just gave in! On ep 5
1. Liar game = excellent cast, promising story, modern, addictive !
2. Kill me heal me = love jisung, love the story 7 different personalities.
3. Drinking solo = the best comedy drama i've ever seen. Lol
It Started with a Kiss/They Kiss Again
Ugly Alert
Woody Sambo
Faith
City Hunter
Nang Rai Sai Lab
You're all Surrounded
Skip Beat!
Down With Love
Bride of the Century