Their rarity and connection to official competitions make them valuable collector items
Gholdengo EX's attack does 50 damage times the amount of energy you discard from your hand, so if you use Energy Search Pro, you will instantly have 350 damage available from one item, which does not feel fair
Mulldrifter plus some recursion with Grim Harvest helps keep Mulldrifter churning through cards
I really like the squad mechanic because it reminds me of the unleash mechanic from the Eternal card game
Here, it's also important to note that Unbound Flourishing's ability stacks, so things will get our of hand quickly if we happen to have multiple copies on the battlefield
Then Mishra, Artificer Prodigy triggers, letting you search for that original artifact and put it into play