Heart of Lorwyn

Whenever an opponent plays a land, you may pay
{g}{w}. If you do, create a 1/1 green Elf Druid creature token.

Whenever an opponent casts an instant or sorcery, you may pay {u}{b}. If you do, create a 1/1 blue Faerie creature token with flying.

Whenever an opponent casts an artifact or enchantment, you may pay {r} and 1 life. If you do, create a Clue, Food, or Treasure token