I thought Mark Antony's death season was amazing, as was Cleopatra's. Vorenus's death was aptly sad, and I loved that his children finally forgave him. Love how it ended, too, with Vorenus telling young Caeserion, "Look, about your father--", of corse implying that he will tell him the truth once and for all.
Atia continues to amaze. Her final lines and looks made the series finale truly special in my view. She expressed such breadth and skill of acting in those final scenes, where she looked at her son and realized what a monster he had become. And of course, there was her final line, spoken to Livia, which I think is one of the best in the series: "I know who you are. I can see you. You're swearing now that someday, you'll destroy me. Remember, far better women than you have sworn to do the same. Go look for them now."