U/G Mill Idea combo

, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Copy target instant or sorcery spell. You may choose new targets for the copy.

As an additional cost to cast this spell, sacrifice a land. Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Landfall — Whenever a land you control enters, target player mills three cards. (They put the top three cards of their library into their graveyard.)

Landfall — Whenever a land you control enters, add one mana of any color.