Star of Extinction

Destroy target land. Star of Extinction deals 20 damage to each creature and each planeswalker.

Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Fraying Omnipotence

Each player loses half their life, then discards half the cards in their hand, then sacrifices half the creatures they control of their choice. Round up each time.

Nemesis of Reason

Whenever this creature attacks, defending player mills ten cards.

Rite of Passage

Whenever a creature you control is dealt damage, put a +1/+1 counter on it. (It must survive the damage to get the counter.)

Undermine

Counter target spell. Its controller loses 3 life.

Parcelbeast

Mutate {G}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
{1}, {T}: Look at the top card of your library. If it's a land card, you may put it onto the battlefield. If you don't put the card onto the battlefield, put it into your hand.

Aether Flash

Whenever a creature enters, this enchantment deals 2 damage to it.

Herd Baloth

Whenever one or more +1/+1 counters are put on this creature, you may create a 4/4 green Beast creature token.

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Boseiju, Who Shelters All

Boseiju enters tapped.
{T}, Pay 2 life: Add {C}. If that mana is spent on an instant or sorcery spell, that spell can't be countered.

Stuffy Doll

Indestructible
As this creature enters, choose a player.
Whenever this creature is dealt damage, it deals that much damage to the chosen player.
{T}: This creature deals 1 damage to itself.

Gratuitous Violence

If a creature you control would deal damage to a permanent or player, it deals double that damage instead.

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Lord of Extinction

Lord of Extinction's power and toughness are each equal to the number of cards in all graveyards.