What does a high fantasy franchise about swords and dragons and ice zombies have to do with Apple TV's most grounded spy series straight out of Cold War thrillers of old? Not much, admittedly, unless you count the crossover appeal between the political intrigue of "Game of Thrones" and the espionage drama of "Slow Horses." (In this scenario, we're assuming you've already re-watched the brilliant "A Knight of the Seven Kingdoms" Season 1 to help scratch that itch.) We have the perfect solution: Watch a wildly different genre series that just so happens to star many of the same cast members. By the time you're up to speed on the impending release of "Slow Horses" Season 6, you might find the long wait for the final season "House of the Dragon" suddenly feels a little more bearable.