Take a look at this deck, and in particular the sideboard: Saito Zoo Tomoharu Saito My point is, if you have access to high-impact cards for a certain matchup, then play with them
You may actually see more than six however you probably won't be able to usefully play all of them as they will require different threats and support to the others
Fanatic of Mogis Instead of including the god Mogis, God of Slaughter who has a great pinging ability, Ill include Fanatic of Mogis for its potentially massive direct damage
As one of Magic: The Gatherings most popular and powerful planeswalkers, Jace Beleren has seen plenty of iterations and planeswalker designs over the years
Invasion of Innistrad You knew we were headed here, and its definitely full of flavor
Effects that interact with spells (such as Saruman's Trickery) won't affect them