The Curve Keeper [Un-Known Event Playtest Cards]

Creatures you control get +X/+0, where X is the greatest number of consecutive nonland, nontoken permanents in a mana curve you control. (For example, if you have permanents with mana value 3, 4, and 5, creatures you control get+3/+0. If you’re missing 4, they only get +1/+0.)