Naked Singularity

Cumulative upkeep {3} (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.)
If tapped for mana, Plains produce {R}, Islands produce {G}, Swamps produce {W}, Mountains produce {U}, and Forests produce {B} instead of any other type.

Mages' Contest

You and target spell's controller bid life. You start the bidding with a bid of 1. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid. If you win the bidding, counter that spell.

Champions of Minas Tirith

When Champions of Minas Tirith enters, you become the monarch.
At the beginning of combat on each opponent's turn, if you're the monarch, that opponent may pay {X}, where X is the number of cards in their hand. If they don't, they can't attack you this combat.

The Seventh Doctor

Whenever The Seventh Doctor attacks, choose a card in your hand. Defending player guesses whether that card's mana value is greater than the number of artifacts you control. If they guessed wrong, you may cast it without paying its mana cost. If you don't cast a spell this way, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Benediction of Moons

You gain 1 life for each player.
Haunt (When this spell card is put into a graveyard after resolving, exile it haunting target creature.)
When the creature Benediction of Moons haunts dies, you gain 1 life for each player.

Prisoner's Dilemma

Each opponent secretly chooses silence or snitch, then the choices are revealed. If each opponent chose silence, Prisoner's Dilemma deals 4 damage to each of them. If each opponent chose snitch, Prisoner's Dilemma deals 8 damage to each of them. Otherwise, Prisoner's Dilemma deals 12 damage to each opponent who chose silence.
Flashback {5}{R}{R}

Battering Ram

At the beginning of combat on your turn, Battering Ram gains banding until end of combat. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's blocking.)
Whenever Battering Ram becomes blocked by a Wall, destroy that Wall at end of combat.

Helm of Chatzuk

{1}, {T}: Target creature gains banding until end of turn. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding a player controls are blocking or being blocked by a creature, that player divides that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Camel

Banding (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)
As long as Camel is attacking, prevent all damage Deserts would deal to Camel and to creatures banded with Camel.

Dance of the Dead

Enchant creature card in a graveyard
When Dance of the Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Dance of the Dead." Put enchanted creature card onto the battlefield tapped under your control and attach Dance of the Dead to it. When Dance of the Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets +1/+1 and doesn't untap during its controller's untap step.
At the beginning of the upkeep of enchanted creature's controller, that player may pay {1}{B}. If the player does, untap that creature.

Island

Bottomless Vault

Bottomless Vault enters tapped.
You may choose not to untap Bottomless Vault during your untap step.
At the beginning of your upkeep, if Bottomless Vault is tapped, put a storage counter on it.
{T}, Remove any number of storage counters from Bottomless Vault: Add {B} for each storage counter removed this way.

Mirror Universe

{T}, Sacrifice Mirror Universe: Exchange life totals with target opponent. Activate only during your upkeep.

Necromancy

You may cast Necromancy as though it had flash. If you cast it any time a sorcery couldn't have been cast, the controller of the permanent it becomes sacrifices it at the beginning of the next cleanup step.
When Necromancy enters, if it's on the battlefield, it becomes an Aura with "enchant creature put onto the battlefield with Necromancy." Put target creature card from a graveyard onto the battlefield under your control and attach Necromancy to it. When Necromancy leaves the battlefield, that creature's controller sacrifices it.

Mercadian Bazaar

Mercadian Bazaar enters tapped.
{T}: Put a storage counter on Mercadian Bazaar.
{T}, Remove any number of storage counters from Mercadian Bazaar: Add {R} for each storage counter removed this way.

Guff Rewrites History

For each player, choose target nonenchantment, nonland permanent that player controls. Those permanents' owners shuffle them into their libraries. Each player who controlled one of those permanents exiles cards from the top of their library until they exile a nonland card, then puts the rest on the bottom of their library in a random order. Each player may cast the nonland card they exiled without paying its mana cost.

Chains of Mephistopheles

If a player would draw a card except the first one they draw in each of their draw steps, that player discards a card instead. If the player discards a card this way, they draw a card. If the player doesn't discard a card this way, they mill a card.

Breena, the Demagogue

Flying
Whenever a player attacks one of your opponents, if that opponent has more life than another of your opponents, that attacking player draws a card and you put two +1/+1 counters on a creature you control.

Struggle for Sanity

Target opponent reveals their hand. That player exiles a card from it, then you exile a card from it. Repeat this process until all cards in that hand have been exiled. That player returns the cards they exiled this way to their hand and puts the rest into their graveyard.

Aether Hub

When Aether Hub enters, you get {E} (an energy counter).
{T}: Add {C}.
{T}, Pay {E}: Add one mana of any color.

Gemstone Caverns

If Gemstone Caverns is in your opening hand and you're not the starting player, you may begin the game with Gemstone Caverns on the battlefield with a luck counter on it. If you do, exile a card from your hand.
{T}: Add {C}. If Gemstone Caverns has a luck counter on it, instead add one mana of any color.

Swamp

Dimensional Breach

Exile all permanents. For as long as any of those cards remain exiled, at the beginning of each player's upkeep, that player returns one of the exiled cards they own to the battlefield.

Tawnos's Coffin

You may choose not to untap Tawnos's Coffin during your untap step.
{3}, {T}: Exile target creature and all Auras attached to it. Note the number and kind of counters that were on that creature. When Tawnos's Coffin leaves the battlefield or becomes untapped, return that exiled card to the battlefield under its owner's control tapped with the noted number and kind of counters on it. If you do, return the other exiled cards to the battlefield under their owner's control attached to that permanent.

Season of the Witch

At the beginning of your upkeep, sacrifice Season of the Witch unless you pay 2 life.
At the beginning of the end step, destroy all untapped creatures that didn't attack this turn, except for creatures that couldn't attack.

Rushwood Grove

Rushwood Grove enters tapped.
{T}: Put a storage counter on Rushwood Grove.
{T}, Remove any number of storage counters from Rushwood Grove: Add {G} for each storage counter removed this way.

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Sorrow's Path

{T}: Choose two target blocking creatures controlled by the same opponent. If each of those creatures could block all creatures that the other is blocking, remove both of them from combat. Each one then blocks all creatures the other was blocking.
Whenever Sorrow's Path becomes tapped, it deals 2 damage to you and each creature you control.

Space Beleren

Space sculptor (Space Beleren divides the battlefield into alpha, beta, and gamma sectors. If a creature isn't assigned to a sector, its controller assigns it to one. Opponents assign first.)
+1: Creatures in each sector can be blocked this turn only by creatures in the same sector.
−1: Put a +1/+1 counter on each creature in the sector of your choice.
−5: Destroy all creatures in the sector of your choice.

Subterranean Hangar

Subterranean Hangar enters tapped.
{T}: Put a storage counter on Subterranean Hangar.
{T}, Remove any number of storage counters from Subterranean Hangar: Add {B} for each storage counter removed this way.

Wand of Ith

{3}, {T}: Target player reveals a card at random from their hand. If it's a land card, that player discards it unless they pay 1 life. If it isn't a land card, the player discards it unless they pay life equal to its mana value. Activate only during your turn.

Shared Fate

If a player would draw a card, that player exiles the top card of one of their opponents' libraries face down instead.
Each player may look at cards they exiled with Shared Fate, and they may play lands and cast spells from among those cards.

Old Man of the Sea

You may choose not to untap Old Man of the Sea during your untap step.
{T}: Gain control of target creature with power less than or equal to Old Man of the Sea's power for as long as Old Man of the Sea remains tapped and that creature's power remains less than or equal to Old Man of the Sea's power.

Ayesha Tanaka

Banding (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)
{T}: Counter target activated ability from an artifact source unless that ability's controller pays {W}. (Mana abilities can't be targeted.)

Dead Ringers

Destroy two target nonblack creatures unless either one is a color the other isn't. They can't be regenerated.

Oracle en-Vec

{T}: Target opponent chooses any number of creatures they control. During that player's next turn, the chosen creatures attack if able, and other creatures can't attack. At the beginning of that turn's end step, destroy each of the chosen creatures that didn't attack this turn. Activate only during your turn.

Leeching Lurker

Lifelink
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Curse of Leeches

Enchant player
As this permanent transforms into Curse of Leeches, attach it to a player.
At the beginning of enchanted player's upkeep, they lose 1 life and you gain 1 life.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Curse of Leeches // Leeching Lurker

Raging River

Whenever one or more creatures you control attack, each defending player divides all creatures without flying they control into a "left" pile and a "right" pile. Then, for each attacking creature you control, choose "left" or "right." That creature can't be blocked this combat except by creatures with flying and creatures in a pile with the chosen label.

Camouflage

Cast this spell only during your declare attackers step.
This turn, instead of declaring blockers, each defending player chooses any number of creatures they control and divides them into a number of piles equal to the number of attacking creatures for whom that player is the defending player. Creatures those players control that can block additional creatures may likewise be put into additional piles. Assign each pile to a different one of those attacking creatures at random. Each creature in a pile that can block the creature that pile is assigned to does so. (Piles can be empty.)

Yavimaya, Cradle of Growth

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

Drop of Honey

At the beginning of your upkeep, destroy the creature with the least power. It can't be regenerated. If two or more creatures are tied for least power, you choose one of them.
When there are no creatures on the battlefield, sacrifice Drop of Honey.

Goblin Bomb

At the beginning of your upkeep, you may flip a coin. If you win the flip, put a fuse counter on Goblin Bomb. If you lose the flip, remove a fuse counter from Goblin Bomb.
Remove five fuse counters from Goblin Bomb and sacrifice it: It deals 20 damage to target player or planeswalker.

Simulacrum

You gain life equal to the damage dealt to you this turn. Simulacrum deals damage to target creature you control equal to the damage dealt to you this turn.

Floodgate

Defender
When Floodgate has flying, sacrifice it.
When Floodgate leaves the battlefield, it deals damage to each nonblue creature without flying equal to half the number of Islands you control, rounded down.

Ravenloft Adventurer

When Ravenloft Adventurer enters, you take the initiative.
If a creature an opponent controls would die, instead exile it and put a hit counter on it.
Whenever Ravenloft Adventurer attacks, if you've completed a dungeon, defending player loses 1 life for each card they own in exile with a hit counter on it.

Timesifter

At the beginning of each upkeep, each player exiles the top card of their library. The player who exiled the card with the highest mana value takes an extra turn after this one. If two or more players' cards are tied for highest, the tied players repeat this process until the tie is broken.

Guardian Beast

As long as Guardian Beast is untapped, noncreature artifacts you control can't be enchanted, they have indestructible, and other players can't gain control of them. This effect doesn't remove Auras already attached to those artifacts.

Arcum's Whistle

{3}, {T}: Choose target non-Wall creature the active player has controlled continuously since the beginning of the turn. That player may pay {X}, where X is that mana value. If they don't pay, the creature attacks this turn if able, and at the beginning of the next end step, destroy it if it didn't attack this turn. Activate only before attackers are declared.

Wall of Shields

Defender (This creature can't attack.)
Banding (If any creatures with banding you control are blocking a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by.)

Plains

Drought

At the beginning of your upkeep, sacrifice Drought unless you pay {W}{W}.
Spells cost an additional "Sacrifice a Swamp" to cast for each black mana symbol in their mana costs.
Activated abilities cost an additional "Sacrifice a Swamp" to activate for each black mana symbol in their activation costs.

Ice Cauldron

{X}, {T}: You may exile a nonland card from your hand. You may cast that card for as long as it remains exiled. Put a charge counter on Ice Cauldron and note the type and amount of mana spent to pay this activation cost. Activate only if there are no charge counters on Ice Cauldron.
{T}, Remove a charge counter from Ice Cauldron: Add Ice Cauldron's last noted type and amount of mana. Spend this mana only to cast the last card exiled with Ice Cauldron.

Mindbender Spores

Defender (This creature can't attack.)
Flying
Whenever Mindbender Spores blocks a creature, put four fungus counters on that creature. The creature gains "This creature doesn't untap during your untap step if it has a fungus counter on it" and "At the beginning of your upkeep, remove a fungus counter from this creature."

Chaos Moon

At the beginning of each upkeep, count the number of permanents. If the number is odd, until end of turn, red creatures get +1/+1 and whenever a player taps a Mountain for mana, that player adds an additional {R}. If the number is even, until end of turn, red creatures get -1/-1 and if a player taps a Mountain for mana, that Mountain produces colorless mana instead of any other type.

Panglacial Wurm

Trample
While you're searching your library, you may cast Panglacial Wurm from your library.

Illusionary Mask

{X}: You may choose a creature card in your hand whose mana cost could be paid by some amount of, or all of, the mana you spent on {X}. If you do, you may cast that card face down as a 2/2 creature spell without paying its mana cost. If the creature that spell becomes as it resolves has not been turned face up and would assign or deal damage, be dealt damage, or become tapped, instead it's turned face up and assigns or deals damage, is dealt damage, or becomes tapped. Activate only as a sorcery.

Tolaria

{T}: Add {U}.
{T}: Target creature loses banding and all "bands with other" abilities until end of turn. Activate only during any upkeep step.

Reality Twist

Cumulative upkeep {1}{U}{U} (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.)
If tapped for mana, Plains produce {R}, Swamps produce {G}, Mountains produce {W}, and Forests produce {B} instead of any other type.

Remove Enchantments

Return to your hand all enchantments you both own and control, all Auras you own attached to permanents you control, and all Auras you own attached to attacking creatures your opponents control. Then destroy all other enchantments you control, all other Auras attached to permanents you control, and all other Auras attached to attacking creatures your opponents control.

Takklemaggot

Enchant creature
At the beginning of the upkeep of enchanted creature's controller, put a -0/-1 counter on that creature.
When enchanted creature dies, that creature's controller chooses a creature that Takklemaggot could enchant. If the player does, return Takklemaggot to the battlefield under your control attached to that creature. If they don't, return Takklemaggot to the battlefield under your control as a non-Aura enchantment. It loses "enchant creature" and gains "At the beginning of that player's upkeep, Takklemaggot deals 1 damage to that player."

Mountain

Urborg, Tomb of Yawgmoth

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

Cooperation

Enchant creature
Enchanted creature has banding. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding a player controls are blocking or being blocked by a creature, that player divides that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Tyrite Sanctum

{T}: Add {C}.
{2}, {T}: Target legendary creature becomes a God in addition to its other types. Put a +1/+1 counter on it.
{4}, {T}, Sacrifice Tyrite Sanctum: Put an indestructible counter on target God.

Clockwork Avian

Flying
Clockwork Avian enters with four +1/+0 counters on it.
At end of combat, if Clockwork Avian attacked or blocked this combat, remove a +1/+0 counter from it.
{X}, {T}: Put up to X +1/+0 counters on Clockwork Avian. This ability can't cause the total number of +1/+0 counters on Clockwork Avian to be greater than four. Activate only during your upkeep.

Starscream, Seeker Leader

Living metal (During your turn, this Vehicle is also a creature.)
Flying, menace, haste
Whenever Starscream deals combat damage to a player, if there is no monarch, that player becomes the monarch.
Whenever you become the monarch, convert Starscream.

Starscream, Power Hungry

More Than Meets the Eye {2}{B} (You may cast this card converted for {2}{B}.)
Flying
Whenever you draw a card, if you're the monarch, target opponent loses 2 life.
Whenever one or more creatures deal combat damage to you, convert Starscream.

Starscream, Power Hungry // Starscream, Seeker Leader

Baton of Morale

{2}: Target creature gains banding until end of turn. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding a player controls are blocking or being blocked by a creature, that player divides that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Rilsa Rael, Kingpin

Deathtouch
When Rilsa Rael, Kingpin enters, you take the initiative.
Whenever you attack, target attacking creature gains deathtouch until end of turn. If you've completed a dungeon, that creature also gets +5/+0 and gains first strike and menace until end of turn.

Wall of Caltrops

Defender (This creature can't attack.)
Whenever Wall of Caltrops blocks a creature, if at least one other Wall creature is blocking that creature and no non-Wall creatures are blocking that creature, Wall of Caltrops gains banding until end of turn. (If any creatures with banding you control are blocking a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by.)

Elrond of the White Council

Secret council — When Elrond of the White Council enters, each player secretly votes for fellowship or aid, then those votes are revealed. For each fellowship vote, the voter chooses a creature they control. You gain control of each creature chosen this way, and they gain "This creature can't attack its owner." Then for each aid vote, put a +1/+1 counter on each creature you control.

Saprazzan Cove

Saprazzan Cove enters tapped.
{T}: Put a storage counter on Saprazzan Cove.
{T}, Remove any number of storage counters from Saprazzan Cove: Add {U} for each storage counter removed this way.

Humility

All creatures lose all abilities and have base power and toughness 1/1.

Wheel of Misfortune

Each player secretly chooses a number 0 or greater, then all players reveal those numbers simultaneously and determine the highest and lowest numbers revealed this way. Wheel of Misfortune deals damage equal to the highest number to each player who chose that number. Each player who didn't choose the lowest number discards their hand, then draws seven cards.

Eye of the Storm

Whenever a player casts an instant or sorcery card, exile it. Then that player copies each instant or sorcery card exiled with Eye of the Storm. For each copy, the player may cast the copy without paying its mana cost.

Word of Command

Look at target opponent's hand and choose a card from it. You control that player until Word of Command finishes resolving. The player plays that card if able. While doing so, the player can activate mana abilities only if they're from lands that player controls and only if mana they produce is spent to activate other mana abilities of lands the player controls and/or to play that card. If the chosen card is cast as a spell, you control the player while that spell is resolving.

Forest

Goblin Game

Each player hides at least one item, then all players reveal them simultaneously. Each player loses life equal to the number of items they revealed. The player who revealed the fewest items then loses half their life, rounded up. If two or more players are tied for fewest, each loses half their life, rounded up.

Each player loses a third of their life, then discards a third of the cards in their hand, then sacrifices a third of the creatures they control of their choice, then sacrifices a third of the lands they control of their choice. Round up each time.

Fountain of Cho

Fountain of Cho enters tapped.
{T}: Put a storage counter on Fountain of Cho.
{T}, Remove any number of storage counters from Fountain of Cho: Add {W} for each storage counter removed this way.

All Hallow's Eve

Exile All Hallow's Eve with two scream counters on it.
At the beginning of your upkeep, if All Hallow's Eve is exiled with a scream counter on it, remove a scream counter from it. If there are no more scream counters on it, put it into your graveyard and each player returns all creature cards from their graveyard to the battlefield.