When Rain of Riches enters the battlefield, create two Treasure tokens (A Treasure is an artifact with ", Sacrifice this artifact: Add one mana of any color.").
The first spell you cast each turn that mana from a Treasure (A Treasure is an artifact with ", Sacrifice this artifact: Add one mana of any color.") was spent to cast has cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.).
Vintage
Modern
, Sacrifice this artifact: Add one mana of any color.")