Harvest Wurm

When Harvest Wurm enters, sacrifice it unless you return a basic land card from your graveyard to your hand.

Scythe Tiger

Shroud (This creature can't be the target of spells or abilities.)
When Scythe Tiger enters, sacrifice it unless you sacrifice a land.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Spark Elemental

Trample, haste (This creature can deal excess combat damage to the player or planeswalker it's attacking. This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice Spark Elemental.

Valakut Predator

Landfall — Whenever a land you control enters, Valakut Predator gets +2/+2 until end of turn.

Rogue Elephant

When Rogue Elephant enters, sacrifice it unless you sacrifice a Forest.

Tilling Treefolk

When Tilling Treefolk enters, you may return up to two target land cards from your graveyard to your hand.