Roughly every show get so much better when you spot some actor who also is in Game of Thrones
And with so many leading actors (especially as they tend not to survive too long) you often find them. Last I remember to watch was Stephen Dillane as guest star in "The Crown", wasn't too easy to notice.
Thanks for the good tip about Medici: Masters of Florence. Too bad our local Netflix is so bad, but I'll certainly give it a try when I get a chance. Sounds very much like a series I will enjoy (Tudors and both versions of Borgia were ok and some historical dramas like Rome is my all time top5).