Creatures can't attack a player unless that player cast a spell or put a nontoken permanent onto the battlefield during their last turn.

Creatures you control have hexproof. (They can't be the targets of spells or abilities your opponents control.)

{1}{G}: Regenerate target creature.

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Exile target creature an opponent controls. That player reveals cards from the top of their library until a creature card is revealed. The player puts that card onto the battlefield, then shuffles the rest into their library.

Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

{4}, {T}, Exile Brittle Effigy: Exile target creature.

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Whenever Colossal Whale attacks, you may exile target creature defending player controls until Colossal Whale leaves the battlefield. (That creature returns under its owner's control.)

When Contagion Engine enters the battlefield, put a -1/-1 counter on each creature target player controls.

{4}, {T}: Proliferate, then proliferate again. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

{T}, Sacrifice Daring Apprentice: Counter target spell.

Whenever you cast a green spell, you may create a 2/2 green Wolf creature token.

Whenever you cast a blue spell, you may create a 1/1 blue Bird creature token with flying.

Enchant creature

When enchanted creature dies, return that card to the battlefield under your control.

When Fool's Demise is put into a graveyard from the battlefield, return Fool's Demise to its owner's hand.

You may choose not to untap Giant Oyster during your untap step.

{T}: For as long as Giant Oyster remains tapped, target tapped creature doesn't untap during its controller's untap step, and at the beginning of each of your draw steps, put a -1/-1 counter on that creature. When Giant Oyster leaves the battlefield or becomes untapped, remove all -1/-1 counters from the creature.

First strike

{T}: Destroy target artifact if its mana value is equal to the amount of unspent mana you have.

Grim Poppet enters the battlefield with three -1/-1 counters on it.

Remove a -1/-1 counter from Grim Poppet: Put a -1/-1 counter on another target creature.

{1}, {T}: Exile target creature you control.

{7}, {T}: Exile target creature you don't control.

When Helvault is put into a graveyard from the battlefield, return all cards exiled with it to the battlefield under their owners' control.

Kicker {2}{G} (You may pay an additional {2}{G} as you cast this spell.)

If Kavu Titan was kicked, it enters the battlefield with three +1/+1 counters on it and with trample.

When you cast this spell, if you have fewer than seven cards in hand, draw cards equal to the difference.

Menace

Discard a card with mana value X: Counter target spell with mana value X.

Flying

Morph {2}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

When Maelstrom Djinn is turned face up, put two time counters on it and it gains vanishing. (At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)

Other Human creatures you control get +1/+1.

At the beginning of each upkeep, if no spells were cast last turn, transform Mayor of Avabruck.

Each other creature you control that's a Werewolf or a Wolf gets +1/+1.

At the beginning of your end step, create a 2/2 green Wolf creature token.

At the beginning of each upkeep, if a player cast two or more spells last turn, transform Howlpack Alpha.

Flash

When Mystic Snake enters the battlefield, counter target spell.

Flying

Nimbus Swimmer enters the battlefield with X +1/+1 counters on it.

Counter target spell. At the beginning of your next precombat main phase, add X mana in any combination of colors, where X is that spell's mana value.

{X}{X}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)

When Polukranos, World Eater becomes monstrous, it deals X damage divided as you choose among any number of target creatures your opponents control. Each of those creatures deals damage equal to its power to Polukranos.

Destroy target creature. It can't be regenerated. Its controller reveals cards from the top of their library until they reveal a creature card. The player puts that card onto the battlefield, then shuffles all other cards revealed this way into their library.

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Exile target permanent.

Enchant creature

At the beginning of the upkeep of enchanted creature's controller, that player sacrifices that creature unless they pay {2}.

When Slow Motion is put into a graveyard from the battlefield, return Slow Motion to its owner's hand.

When Spine of Ish Sah enters the battlefield, destroy target permanent.

When Spine of Ish Sah is put into a graveyard from the battlefield, return Spine of Ish Sah to its owner's hand.

({2/G} can be paid with any two mana or with {G}. This card's mana value is 6.)

Until end of turn, target creature gets +4/+4 and gains trample, wither, and "When this creature attacks, target creature blocks it this turn if able." (It deals damage to creatures in the form of -1/-1 counters.)

{T}: Add {C}.

{7}, {T}, Sacrifice Unstable Obelisk: Destroy target permanent.

Walking Ballista enters the battlefield with X +1/+1 counters on it.

{4}: Put a +1/+1 counter on Walking Ballista.

Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.