When Thopter Engineer enters the battlefield, create a 1/1 colorless Thopter artifact creature token with flying. Artifact creatures you control have haste.
When Avenger of Zendikar enters the battlefield, create a 0/1 green Plant creature token for each land you control. Landfall — Whenever a land enters the battlefield under your control, you may put a +1/+1 counter on each Plant creature you control.
When Borderland Explorer enters the battlefield, each player may discard a card. Each player who discarded a card this way may search their library for a basic land card, reveal it, put it into their hand, then shuffle.
Trample Centaur Vinecrasher enters the battlefield with a number of +1/+1 counters on it equal to the number of land cards in all graveyards. Whenever a land card is put into a graveyard from anywhere, you may pay {G}{G}. If you do, return Centaur Vinecrasher from your graveyard to your hand.
Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.
All seeds share a common bond, calling to each other across infinity.
Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle. Threshold — If seven or more cards are in your graveyard, instead search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.