@Naxald unless it is just not your thing, I strongly recommend picking up 1 litre of tears again. healer is also a great drama from your on-hold list, but I always tell people it might take 4 - 5 episodes to get hooked since that's about how long it took me to understand the hype. great script & characters, imo.
Mask - The love story is the main thing to look forward in this drama. Signal - This one I strongly recommend to continue watching it, because the story gets better as the episodes continue and the suspense also gets better and above all the story of the profiler's brother is heartbreaking. Fated to love you - Though it looses strength towards the last couple of episodes the rest of it it's pretty lovely Itazurana kiss - It's a pretty cute drama, light hearted and is not something to take to seriously.
Another Miss Oh can be boring at first, and you can have probls with the male lead. But it'll get better, it's mixed perfeclty the melodrama and comedy kind. But the thing that got me really hooked was Seo Hyun Jin amazing performance, she's daebak.
Boys Over Flowers - Omo! My first drama ever! It has a great storyline and cast. Chaebols, flower boys, poor girl, love triangle, school setting and just the right touch of jealousy to make the butterflies flutter.
Based on your dropped list these are the dramas that I think you should give a second chance. I watched all of them and I personally love them, but there may be some down points but overall I think it was great.
Arang and the Magistrate Goblin (THIS IS THE BEST. PLEASE HIGHLY CONSIDER IT) Hotel King Hwarang Amazing Boyfriend You Who Came From The Stars
I hate Scarlet Heart Ryeo. Dropped at episode 10 or 11, as I heard it'll have tragic ending, I dropped to watch to avoid disappointment. Let me just hold on to nice memories when Wang So and Hae Soo fell in love. Second chance? eotteohge?