Any sweet,  romantic  dramas  without  a 2nd female lead? 

No action, historical, crime, political, high school, medical dramas. (+nothing i have already completed/dropped  pls)

Interested only in Korean, Japanese and Taiwanese ones.

  • Kahogo no Kahoko
  • Soratobu Kouhoushitsu
  • Tatta Hitotsu no Koi
  • Tosuzen desuga ashita kekkonshimasu
  • We married as a job
  • Boku, Unmei no Hito desu
  • Sekai ichi muzukashii koi
  • Live up to your name
  • Weightlifting fairy (it does has a 2nd female lead but she barely does anything against the couple)
  • Kill me heal me
  • Something about 1%

I've included some dramas that have a big legal component and some crime, but I wouldn't consider them crime dramas. It's possible that there may have been a female character who likes the ML in some of these that was so minor I've forgotten about her. 

Some of my favourites:

  • Healer (reporters / some action / a very small amount of politics)
  • Coffee Prince (gender bender) 
  • Bromance (gender bender / some action)
  • I Hear Your Voice (Noona / law with some crime / fantasy element) 
  • While You Were Sleeping (law with some crime / fantasy element) 

Also good :

  • Go Ho's Starry Night (office)
  • Queen In Hyun's Man (time travel, so some historical bits but mostly in the present)
  • Witch's Romance (Noona / office)
  • It's Okay, That's Love (not a standard medical drama, but psychology / mental illnesses are a huge component)
  • Kill Me, Heal Me (also involves psychology / multiple personalities)
  • Bring It On, Ghost / Let's Fight Ghost (fantasy / you could technically call the fights action / crime I guess, but it's really not that serious)
  • Pinocchio (reporters / some crime / some revenge)

Not in my personal top 40, but worth checking out based on your criteria: 

  • Heartstrings (music majors / there's a female rival but I can't remember if she had feelings for the ML or not)
  • Strongest Deliveryman (literally food delivery... workplace?)
  • Suspicious Partner (law / not really much crime as far as I can remember)
  • You're Beautiful (gender bender / music / idols)
  • You Who Came from the Stars (alien / sci-fi in the present with some historical elements)
  • Goblin (fantasy in the present with some historical elements)

Dramas where there is a female character who likes the ML and I remember that she exists, but she played a very minor role:

  • My Secret Romance (office)
  • W (fantasy / sci-fi with some action / crime)
  • From 5 to 9 / 5-ji Kara 9-ji Made (reverse harem)
  • Personal Taste (as far as I can remember the main love rival is male)

@fanitha ty,  3-4 of them look nice

@AH  seen most of them

You may also try "Falling for innocence"

One of my absolute favorites- Tokyo Bandwagon.

Its Slice of life but very heartwarming family drama also, about 10 episodes. Give it go

Yamada kun and the seven witches

Shopping king Louis

Sassy Go Go

My mr mermaid

Strong woman bong soon

Goblin

Hwarang

High end crush

Reply 1997

K2

Descendant of the sun

My love from the star

Queen in hyung man

LoveO2O chinese drama