Plains

Guardian of the Great Door

As an additional cost to cast this spell, tap four untapped artifacts, creatures, and/or lands you control.
Flying

Waylaying Pirates

When Waylaying Pirates enters, if you control an artifact, tap target artifact or creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

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.

Mischievous Pup

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, return up to one other target permanent you control to its owner's hand.

Family Reunion

Choose one —
• Creatures you control get +1/+1 until end of turn.
• Creatures you control gain hexproof until end of turn. (They can't be the targets of spells or abilities your opponents control.)

Helping Hand

Return target creature card with mana value 3 or less from your graveyard to the battlefield tapped.

Oteclan Levitator

Flying
Whenever Oteclan Levitator attacks, target attacking creature without flying gains flying until end of turn.

Oteclan Landmark

When Oteclan Landmark enters, scry 2.
Craft with artifact {2}{W} ({2}{W}, 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.)

Oteclan Landmark // Oteclan Levitator

Ancestral Reminiscence

Cosmium Kiln

When Cosmium Kiln enters, create two 1/1 colorless Gnome artifact creature tokens.
Creatures you control get +1/+1.

Clay-Fired Bricks

When Clay-Fired Bricks enters, search your library for a basic Plains card, reveal it, put it into your hand, then shuffle. You gain 2 life.
Craft with artifact {5}{W}{W} ({5}{W}{W}, 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.)

Clay-Fired Bricks // Cosmium Kiln

Hidden Cataract

Hidden Cataract enters tapped.
{T}: Add {U}.
{4}{U}, {T}, Sacrifice Hidden Cataract: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Might of the Ancestors

At the beginning of combat on your turn, target creature you control gets +2/+0 and gains vigilance until end of turn.

Master's Manufactory

{T}: Create a 4/4 white and blue Golem artifact creature token. Activate only if Master's Manufactory or another artifact entered the battlefield under your control this turn.

Master's Guide-Mural

When Master's Guide-Mural enters, create a 4/4 white and blue Golem artifact creature token.
Craft with artifact {4}{W}{W}{U} ({4}{W}{W}{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.)

Master's Guide-Mural // Master's Manufactory

Tinker's Tote

When Tinker's Tote enters, create two 1/1 colorless Gnome artifact creature tokens.
{W}, Sacrifice Tinker's Tote: You gain 3 life.

Sunken Citadel

Sunken Citadel enters tapped. As it enters, choose a color.
{T}: Add one mana of the chosen color.
{T}: Add two mana of the chosen color. Spend this mana only to activate abilities of land sources.

Island

Ironpaw Aspirant

When Ironpaw Aspirant enters, put a +1/+1 counter on target creature.

Acrobatic Leap

Target creature gets +1/+3 and gains flying until end of turn. Untap it.

Get Lost

Destroy target creature, enchantment, or planeswalker. Its controller creates two Map tokens. (They're artifacts with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

Akal Pakal, First Among Equals

At the beginning of each player's end step, if an artifact entered the battlefield under your control this turn, look at the top two cards of your library. Put one of them into your hand and the other into your graveyard.

Hermitic Nautilus

Vigilance
{1}{U}: Hermitic Nautilus gets +3/-3 until end of turn.

Staunch Crewmate

When Staunch Crewmate enters, look at the top four cards of your library. You may reveal an artifact or Pirate card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

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.)

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.)

Oaken Siren

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

Cartographer's Companion

When Cartographer's Companion 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.")

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

Miner's Guidewing

Flying, vigilance
When Miner's Guidewing dies, target creature you control 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 that creature, then put the card back or put it into your graveyard.)