Kalypso:
Currently trying to figure out which one to sink into... I've been in a bit of a drama slump lately.
These are my personal favorite historical dramas (that you haven't seen). I'm not sure these are necessarily the best choices to pull you out of a slump, since for me, personally, these were all dramas that grew on me over time rather than grabbing me right from the beginning, but all of them are great, in my opinion (also some of my favorite soundtracks).
Six Flying Dragons - Follows a number major historical figures from the end of the Goryeo period (late 14th century). Heavily focuses on the politics (and actually follows real events with some degree of accuracy, more than many dramas) and conflicting ideologies. The characters are compelling, but not always likable. There's also lots of action/martial arts. One off the darker historical dramas I've seen.
Mr. Sunshine - This is a highly stylized sort of cross between British period drama and classic Korean melodrama with a touch more politics. Visually gorgeous and emotional poignant. The characters are very lovable, and though it's not a comedy, it can be quite funny. Set in the early 20th century as Korea is Westernizing.
The Rebel - Set in Joseon (in the late 15th century), this is a "hero of the people" story based on Hong Gil Dong (sometimes described as "Korean Robin Hood") and his charming band of sidekicks. Of the ones on this list, this is the most "fun" drama. It does have politics and some heavy parts, but it doesn't take itself too seriously.
Based on the historical dramas on you've previously watched, I kinda think Six Flying Dragons might be most to your taste, but it's also twice the length of the other two, and if you're in the mood for romance, it's not the drama to choose.
Also, welcome!
Plushpriestess:
I guess that means it is time to watch something fluffy and light until I can get through the backlog of emotions. Any suggestions?!
I'm probably the worst person to ask for recommendations for fluffy historicals, so hopefully someone else can help more. My top choice would be Love in the Moonlight, basically because the main couple is just so adorable. The production is also good. The plot is mediocre, but that's generally the case for the fluffy ones. It doesn't look like you've watched any sageuks before, but this would be an easy introduction, I think, because it's not very serious.