Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Taiga

Sea of Clouds

Sea of Clouds enters the battlefield tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Farewell

Choose one or more —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all graveyards.

Volcanic Island

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Trouble in Pairs

If an opponent would begin an extra turn, that player skips that turn instead.
Whenever an opponent attacks you with two or more creatures, draws their second card each turn, or casts their second spell each turn, you draw a card.

Rejuvenating Springs

Rejuvenating Springs enters the battlefield tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Roaming Throne

Ward {2}
As Roaming Throne enters the battlefield, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Bountiful Promenade

Bountiful Promenade enters the battlefield tapped unless you have two or more opponents.
{T}: Add {G} or {W}.

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Underground Sea

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Land Tax

At the beginning of your upkeep, if an opponent controls more lands than you, you may search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Vault of Champions

Vault of Champions enters the battlefield tapped unless you have two or more opponents.
{T}: Add {W} or {B}.

Plateau

Tropical Island

Scrubland

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Undergrowth Stadium

Undergrowth Stadium enters the battlefield tapped unless you have two or more opponents.
{T}: Add {B} or {G}.

Training Center

Training Center enters the battlefield tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Badlands

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Bayou

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Gaea's Cradle

{T}: Add {G} for each creature you control.

Field of the Dead

Field of the Dead enters the battlefield tapped.
{T}: Add {C}.
Whenever Field of the Dead or another land enters the battlefield under your control, if you control seven or more lands with different names, create a 2/2 black Zombie creature token.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Spectator Seating

Spectator Seating enters the battlefield tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Luxury Suite

Luxury Suite enters the battlefield tapped unless you have two or more opponents.
{T}: Add {B} or {R}.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Command Tower

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Tempt with Discovery

Tempting offer — Search your library for a land card and put it onto the battlefield. Each opponent may search their library for a land card and put it onto the battlefield. For each opponent who searches a library this way, search your library for a land card and put it onto the battlefield. Then each player who searched a library this way shuffles.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

The World Tree

The World Tree enters the battlefield tapped.
{T}: Add {G}.
As long as you control six or more lands, lands you control have "{T}: Add one mana of any color."
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice The World Tree: Search your library for any number of God cards, put them onto the battlefield, then shuffle.

Jeska's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Add {R} for each card in target opponent's hand.
• Exile the top three cards of your library. You may play them this turn.

Savannah

Sol Ring

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Sylvan Library

At the beginning of your draw step, you may draw two additional cards. If you do, choose two cards in your hand drawn this turn. For each of those cards, pay 4 life or put the card on top of your library.

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Spire Garden

Spire Garden enters the battlefield tapped unless you have two or more opponents.
{T}: Add {R} or {G}.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Fellwar Stone

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Tundra

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Morphic Pool

Morphic Pool enters the battlefield tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Jeweled Lotus

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

Imperial Seal

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Dockside Extortionist

When Dockside Extortionist enters the battlefield, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

Burgeoning

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.