In my experience, the Game Changers that win the most games are the ones that generate persistent card advantage: Rhystic Study, Smothering Tithe, Necropotence
While this definitely feels like a Commander card, the sheer efficiency here may actually earn it a spot in something like Legacy Death and Taxes
A better way of thinking about this is perhaps to say that it scales well with dead cards as that communicates better how to use it to your advantage
Some of the best cards to pair with Morophon, the Boundless include: Urza's Incubator stacks additional cost reduction effects for your chosen creature type Leyline of Mutation enhances your creature-type synergies even further Vanquisher's Banner provides both card draw and a power boost for your board Chronicle of Victory gives your creatures first strike, trample, +2/+2, and draws you cards 4
And if youre thinking about getting into Magic because this MTG set looks cute, but wonder if itll hold up competitively, I can tell you that Bloomburrow has a solid chunk of great cards, including a bunch of really juiced uncommons