i want yo watch dramas where the side couples are just as cute and lovable as the main couple

I would prefer longer dramas but fine with 16-20 episodes ones too

Descendants of the Sun
Karn La Krang Neung…Nai Hua Jai is the first one that comes to mind

King 2 Hearts is one of my favourites too!! 
Pure 19/ Hearts of 19/ Pure in Heart- 100% cute (and funny)
Definitely High Society
'Discovery of Romance' has a very cute side couple.