Personally the costume director one ^_^ I'm obsessed with costuming so it was so cool to hear Isis talk about her process. She based Moiraine's wardrobe on Picasso's blue period which is just so cool.
The cast, directors, showrunner, and producers all did a press junket in October. Amazon lifted the embargo on that today so everyone is publishing the articles they've had ready to go since then. I'm going to try to collect them here because there is a LOT of really great stuff coming out...