Sol Ring

Arvinox, the Mind Flail

Arvinox, the Mind Flail isn't a creature unless you control three or more permanents you don't own.
At the beginning of your end step, exile the bottom card of each opponent's library face down. For as long as those cards remain exiled, you may look at them, you may cast permanent spells from among them, and you may spend mana as though it were mana of any color to cast those spells.

Arrest

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.

Plateau

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Sacred Foundry

({T}: Add {R} or {W}.)
As Sacred Foundry enters, you may pay 2 life. If you don't, it enters tapped.

Gateway Plaza

Gateway Plaza enters tapped.
When Gateway Plaza enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Undying Rage

Enchant creature
Enchanted creature gets +2/+2 and can't block.
When Undying Rage is put into a graveyard from the battlefield, return Undying Rage to its owner's hand.

Case of the Stashed Skeleton

When this Case enters, create a 2/1 black Skeleton creature token and suspect it. (It has menace and can't block.)
To solve — You control no suspected Skeletons. (If unsolved, solve at the beginning of your end step.)
Solved — {1}{B}, Sacrifice this Case: Search your library for a card, put it into your hand, then shuffle. Activate only as a sorcery.

Delaying Shield

If damage would be dealt to you, put that many delay counters on Delaying Shield instead.
At the beginning of your upkeep, remove all delay counters from Delaying Shield. For each delay counter removed this way, you lose 1 life unless you pay {1}{W}.

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Shadowy Backstreet

({T}: Add {W} or {B}.)
Shadowy Backstreet enters tapped.
When Shadowy Backstreet enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Artist's Talent

(Gain the next level as a sorcery to add its ability.)
Whenever you cast a noncreature spell, you may discard a card. If you do, draw a card.
{2}{R}: Level 2
Noncreature spells you cast cost {1} less to cast.
{2}{R}: Level 3
If a source you control would deal noncombat damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

Raucous Theater

({T}: Add {B} or {R}.)
Raucous Theater enters tapped.
When Raucous Theater enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Plains

Talon Gates of Madara

When Talon Gates of Madara enters, up to one target creature phases out.
{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{4}: Put Talon Gates of Madara from your hand onto the battlefield.

Elegant Parlor

({T}: Add {R} or {W}.)
Elegant Parlor enters tapped.
When Elegant Parlor enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Assemble the Legion

At the beginning of your upkeep, put a muster counter on Assemble the Legion. Then create a 1/1 red and white Soldier creature token with haste for each muster counter on Assemble the Legion.

Alchemist's Talent

(Gain the next level as a sorcery to add its ability.)
When Alchemist's Talent enters, create two tapped Treasure tokens.
{1}{R}: Level 2
Treasures you control have "{T}, Sacrifice this artifact: Add two mana of any one color."
{4}{R}: Level 3
Whenever you cast a spell, if mana from a Treasure was spent to cast it, this Class deals damage equal to that spell's mana value to each opponent.

Orzhov Guildgate

This land enters tapped.
{T}: Add {W} or {B}.

Rakdos Guildgate

This land enters tapped.
{T}: Add {B} or {R}.

Alseid of Life's Bounty

Lifelink
{1}, Sacrifice Alseid of Life's Bounty: Target creature or enchantment you control gains protection from the color of your choice until end of turn.

Archetype of Courage

Creatures you control have first strike.
Creatures your opponents control lose first strike and can't have or gain first strike.

The Black Gate

As The Black Gate enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.
{1}{B}, {T}: Choose a player with the most life or tied for most life. Target creature can't be blocked by creatures that player controls this turn.

Basilisk Gate

{T}: Add {C}.
{2}, {T}: Target creature gets +X/+X until end of turn, where X is the number of Gates you control. Activate only as a sorcery.

Bastion of Remembrance

When Bastion of Remembrance enters, create a 1/1 white Human Soldier creature token.
Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

Archetype of Finality

Creatures you control have deathtouch.
Creatures your opponents control lose deathtouch and can't have or gain deathtouch.

Godless Shrine

({T}: Add {W} or {B}.)
As Godless Shrine enters, you may pay 2 life. If you don't, it enters tapped.

Case of the Crimson Pulse

When this Case enters, discard a card, then draw two cards.
To solve — You have no cards in hand. (If unsolved, solve at the beginning of your end step.)
Solved — At the beginning of your upkeep, discard your hand, then draw two cards.

Case of the Gorgon's Kiss

When this Case enters, destroy up to one target creature that was dealt damage this turn.
To solve — Three or more creature cards were put into graveyards from anywhere this turn. (If unsolved, solve at the beginning of your end step.)
Solved — This Case is a 4/4 Gorgon creature with deathtouch and lifelink in addition to its other types.

Bound in Gold

Enchant permanent
Enchanted permanent can't attack, block, or crew Vehicles, and its activated abilities can't be activated unless they're mana abilities.

Citadel Gate

Citadel Gate enters tapped.
As Citadel Gate enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Mountain

Black Dragon Gate

Black Dragon Gate enters tapped.
As Black Dragon Gate enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Canyon Slough

({T}: Add {B} or {R}.)
Canyon Slough enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Badlands

Blessing of Leeches

Flash
Enchant creature
At the beginning of your upkeep, you lose 1 life.
{0}: Regenerate enchanted creature.

Aegis of the Gods

You have hexproof. (You can't be the target of spells or abilities your opponents control.)

Case of the Uneaten Feast

Whenever a creature you control enters, you gain 1 life.
To solve — You've gained 5 or more life this turn. (If unsolved, solve at the beginning of your end step.)
Solved — Sacrifice this Case: Creature cards in your graveyard gain "You may cast this card from your graveyard" until end of turn.

Boros Guildgate

This land enters tapped.
{T}: Add {R} or {W}.

Brain Maggot

When Brain Maggot enters, target opponent reveals their hand and you choose a nonland card from it. Exile that card until Brain Maggot leaves the battlefield.

Baldur's Gate

{T}: Add {C}.
{2}, {T}: Add X mana of any one color, where X is the number of other Gates you control.

All That Glitters

Enchant creature
Enchanted creature gets +1/+1 for each artifact and/or enchantment you control.

Swamp

Scrubland

Savai Triome

({T}: Add {R}, {W}, or {B}.)
Savai Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Cartouche of Solidarity

Enchant creature you control
When Cartouche of Solidarity enters, create a 1/1 white Warrior creature token with vigilance.
Enchanted creature gets +1/+1 and has first strike. (It deals combat damage before creatures without first strike.)

Ajani's Welcome

Whenever a creature you control enters, you gain 1 life.

Angelic Gift

Enchant creature
When Angelic Gift enters, draw a card.
Enchanted creature has flying.

Ghen, Arcanum Weaver

{R}{W}{B}, {T}, Sacrifice an enchantment: Return target enchantment card from your graveyard to the battlefield.

Cartouche of Zeal

Enchant creature you control
When Cartouche of Zeal enters, target creature can't block this turn.
Enchanted creature gets +1/+1 and has haste. (It can attack and {T} no matter when it came under your control.)

Gond Gate

Gates you control enter untapped.
{T}: Add {C}.
{T}: Add one mana of any color that a Gate you control could produce.

Cartouche of Ambition

Enchant creature you control
When Cartouche of Ambition enters, you may put a -1/-1 counter on target creature.
Enchanted creature gets +1/+1 and has lifelink.

Cliffgate

Cliffgate enters tapped.
As Cliffgate enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Blessed Sanctuary

Prevent all noncombat damage that would be dealt to you and creatures you control.
Whenever a nontoken creature you control enters, create a 2/2 white Unicorn creature token.