I can't seem to find any good romance kdrama.

I feel like I already know every single one of them.

The struggle when you watch too many kdrama T_T

Any good recommendations?

Try Chinese dramas like Eternal Love,Boss and Me and Love o2o. 

Eternal Love is all the hype these days, btw.
Some of the older dramas are pretty good. I really loved Capital Scandal. (^_^)
Underrated, huh? Well I just watched Good Morning, Call on Netflix. It's silly and fluffy, but the production value was decent, and the story line reminded me of Playful Kiss. I enjoyed it! ^.^
Well I looked at your list & you do have a lot on there but I didn't see Let's Eat & Let's Eat 2.  I really liked those!
I think Witch's Romance was very good and very underrated! And while I wouldn't consider it underrated, Oh My Venus is also very good!