Vulpikeet

Mutate {2}{W} (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.)
Flying
Whenever this creature mutates, put a +1/+1 counter on it.

Saiba Cryptomancer

Flash
Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
Hexproof

Migratory Greathorn

Mutate {2}{G} (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.)
Whenever this creature mutates, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Slippery Bogle

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Plains

Forest

Dreamtail Heron

Mutate {3}{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.)
Flying
Whenever this creature mutates, draw a card.

Avenging Hunter

Trample
When Avenging Hunter enters, you take the initiative.

Abundant Growth

Enchant land
When Abundant Growth enters, draw a card.
Enchanted land has "{T}: Add one mana of any color."

Journey to Nowhere

When Journey to Nowhere enters, exile target creature.
When Journey to Nowhere leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile Relic of Progenitus: Exile all graveyards. Draw a card.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Island

Armadillo Cloak

Enchant creature
Enchanted creature gets +2/+2 and has trample.
Whenever enchanted creature deals damage, you gain that much life.

Dust to Dust

Essence Symbiote

Whenever a creature you control mutates, put a +1/+1 counter on that creature and you gain 2 life.

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Brokers Hideout

When Brokers Hideout enters, sacrifice it. When you do, search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle and you gain 1 life.