Merfolk Cave-Diver

Whenever a creature you control explores, Merfolk Cave-Diver gets +1/+0 until end of turn and can't be blocked this turn.

Glorifier of Suffering

When Glorifier of Suffering enters, you may sacrifice another creature or artifact. When you do, put a +1/+1 counter on each of up to two target creatures.

Ancestral Reminiscence

Cogwork Wrestler

Flash
When Cogwork Wrestler enters, target creature an opponent controls gets -2/-0 until end of turn.

Runaway Boulder

Flash
When Runaway Boulder enters, it deals 6 damage to target creature an opponent controls.
Cycling {2} ({2}, Discard this card: Draw a card.)

Orazca Puzzle-Door

{1}, {T}, Sacrifice Orazca Puzzle-Door: Look at the top two cards of your library. Put one of those cards into your hand and the other into your graveyard.

Marauding Brinefang

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Zoetic Glyph

Enchant artifact
Enchanted artifact is a Golem creature with base power and toughness 5/4 in addition to its other types.
When Zoetic Glyph is put into a graveyard from the battlefield, discover 3.

Self-Reflection

Create a token that's a copy of target creature you control.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Confounding Riddle

Choose one —
• Look at the top four cards of your library. Put one of them into your hand and the rest into your graveyard.
• Counter target spell unless its controller pays {4}.

Out of Air

This spell costs {2} less to cast if it targets a creature spell.
Counter target spell.

Oltec Archaeologists

When Oltec Archaeologists enters, choose one —
• Return target artifact card from your graveyard to your hand.
• Scry 3. (Look at the top three cards of your library, then put any number of them on the bottom and the rest on top in any order.)

The Core

(Transforms from Matzalantli.)
Fathomless descent — {T}: Add X mana of any one color, where X is the number of permanent cards in your graveyard.

Matzalantli, the Great Door

{T}: Draw a card, then discard a card.
{4}, {T}: Transform Matzalantli, the Great Door. Activate only if there are four or more permanent types among cards in your graveyard. (Artifact, battle, creature, enchantment, land, and planeswalker are permanent types.)

Matzalantli, the Great Door // The Core

Adaptive Gemguard

Tap two untapped artifacts and/or creatures you control: Put a +1/+1 counter on Adaptive Gemguard. Activate only as a sorcery.

Relic's Roar

Until end of turn, target artifact or creature becomes a Dinosaur artifact creature with base power and toughness 4/3 in addition to its other types.

Eaten by Piranhas

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature loses all abilities and is a black Skeleton creature with base power and toughness 1/1. (It loses all other colors, card types, and creature types.)

Pirate Hat

Equipped creature gets +1/+1 and has "Whenever this creature attacks, draw a card, then discard a card."
Equip Pirate {1}
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Waterwind Scout

Flying
When Waterwind Scout enters, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

Island

Oltec Cloud Guard

Flying
When Oltec Cloud Guard enters, create a 1/1 colorless Gnome artifact creature token.

Oaken Siren

Flying, vigilance
{T}: Add {U}. Spend this mana only to cast an artifact spell or activate an ability of an artifact source.

Plains

Thousand Moons Infantry

Untap Thousand Moons Infantry during each other player's untap step.

Shipwreck Sentry

Defender
As long as an artifact entered the battlefield under your control this turn, Shipwreck Sentry can attack as though it didn't have defender.

River Herald Scout

When River Herald Scout enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Soaring Sandwing

Flying
When Soaring Sandwing enters, you gain 3 life.
Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Chart a Course

Draw two cards. Then discard a card unless you attacked this turn.

Hunter's Blowgun

Equipped creature gets +1/+1.
Equipped creature has deathtouch during your turn. Otherwise, it has reach.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Iceberg Titan

Whenever Iceberg Titan attacks, you may tap or untap target artifact or creature.

Inverted Iceberg

When Inverted Iceberg enters, mill a card, then draw a card. (To mill a card, put the top card of your library into your graveyard.)
Craft with artifact {4}{U}{U} ({4}{U}{U}, Exile this artifact, Exile another artifact you control or an artifact card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Inverted Iceberg // Iceberg Titan

Didact Echo

When Didact Echo enters, draw a card.
Descend 4 — Didact Echo has flying as long as there are four or more permanent cards in your graveyard.