Higher-power decks can also include Thassa's Oracle or Jace, Wielder of Mysteries for their own win conditions, which incidentally means that milling an opponent out could mean that they win the game
Then for chapters two and three, you get to double the number of each type of counter on a creature you control
The deck's commander, Firmuth, Sage of Corrosiveness, is a perfect example of this strategy, as he gets stronger as you mutate creatures under your control
I think the best part of this is that you could target your stuff, or your opponent can, and you still get the benefit across all your creatures
So, Wizards made the partner mechanic, which lets you have two legends in the command zone, as long as they both have partner