Dictate of Karametra
The flash is the entire pivot. A symmetric mana accelerator is the oldest kind of Faustian bargain in green: Heartbeat of Spring, Mana Flare, the whole class of "everyone goes faster" enchantments that almost always help the wrong player most. What separates this one is the ability to land it at instant speed, on the opponent's end step right before your untap, so the extra mana is in play for your full turn while the rest of the table has already passed. Resolve it there, untap, and you alone get to spend the surplus before anyone else draws or taps a land off it; the symmetry that should sink this design collapses into a one-turn head start. The "any type that land produced" clause is quietly broad: it adds a mana matching a type the land made rather than the land's basic color identity, so it plays well with painlands, filter lands, and lands producing colorless or off-color mana, giving you one extra of the right kind each tap regardless of the source. The cost of all this is that it does nothing the turn you have no surplus to spend, and once it sticks it permanently widens every opponent's mana too, handing the advantage back the moment the table cycles around. It is a ramp piece for a deck built to win in a single explosive turn, dressed as a group-hug enchantment, with flash as the lever that decides which of those two cards it actually is.
