Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Defender Put a -0/-1 counter on this creature: Add {G}. Activate only once each turn.

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.

When this creature enters, each opponent loses 1 life and you gain 1 life. Sacrifice a Food: Return this card from your graveyard to the battlefield.

Whenever another nontoken creature you control enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.") Sacrifice three Foods: Return target historic card from your graveyard to your hand. (Artifacts, legendaries, and Sagas are historic.)

Protection from Humans Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card. {B}{B}, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

If it's not your turn, you may exile a green card from your hand rather than pay this spell's mana cost. Destroy up to two target artifacts and/or enchantments.

{T}, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Sacrifice a land: Target creature you control gains shroud until end of turn. (It can't be the target of spells or abilities.)

Flash Flying Artifacts and creatures entering don't cause abilities to trigger.