Nature's Claim

Destroy target artifact or enchantment. Its controller gains 4 life.

Keruga, the Macrosage

Companion — Your starting deck contains only cards with mana value 3 or greater and land cards. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
When Keruga, the Macrosage enters, draw a card for each other permanent you control with mana value 3 or greater.

Negate

Beast Within

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

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Followed Footsteps

Enchant creature
At the beginning of your upkeep, create a token that's a copy of enchanted creature.

Counterspell

Frilled Mystic

Flash
When Frilled Mystic enters, you may counter target spell.

Phantasmal Image

You may have Phantasmal Image enter as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Reclamation Sage

When Reclamation Sage enters, you may destroy target artifact or enchantment.

Voracious Greatshark

Flash
When Voracious Greatshark enters, counter target artifact or creature spell.

Mystic Snake

Flash
When Mystic Snake enters, counter target spell.

Trygon Predator

Flying
Whenever Trygon Predator deals combat damage to a player, you may destroy target artifact or enchantment that player controls.

Clone

You may have Clone enter as a copy of any creature on the battlefield.

Essence Scatter

Venser, Shaper Savant

Flash
When Venser, Shaper Savant enters, return target spell or permanent to its owner's hand.

Draining Whelk

Flash
Flying
When Draining Whelk enters, counter target spell. Put X +1/+1 counters on Draining Whelk, where X is that spell's mana value.

Vizier of Many Faces

You may have Vizier of Many Faces enter as a copy of any creature on the battlefield, except if Vizier of Many Faces was embalmed, the token has no mana cost, it's white, and it's a Zombie in addition to its other types.
Embalm {3}{U}{U}

Clever Impersonator

You may have Clever Impersonator enter as a copy of any nonland permanent on the battlefield.

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Manglehorn

When Manglehorn enters, you may destroy target artifact.
Artifacts your opponents control enter tapped.

Rapid Hybridization

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

Mirror Mockery

Enchant creature
Whenever enchanted creature attacks, you may create a token that's a copy of that creature. Exile that token at end of combat.

Pongify

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