Cavern of Souls

As Cavern of Souls enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

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}.

Faceless Haven

{T}: Add {C}.
{S}{S}{S}: Faceless Haven becomes a 4/3 creature with vigilance and all creature types until end of turn. It's still a land. ({S} can be paid with one mana from a snow source.)

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Ashnod's Altar

Cabal Coffers

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

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Black Sun's Zenith

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Snow-Covered Swamp

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Astral Cornucopia

Astral Cornucopia enters with X charge counters on it.
{T}: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Inventors' Fair

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
{T}: Add {C}.
{4}, {T}, Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

Deepglow Skate

When Deepglow Skate enters, double the number of each kind of counter on any number of target permanents.

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Genesis Chamber

Whenever a nontoken creature enters, if Genesis Chamber is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. Talisman of Dominance deals 1 damage to you.

Rhystic Study

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

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Ornithopter of Paradise

Toxrill, the Corrosive

At the beginning of each end step, put a slime counter on each creature you don't control.
Creatures you don't control get -1/-1 for each slime counter on them.
Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token.
{U}{B}, Sacrifice a Slug: Draw a card.

Malakir Mire

Malakir Mire enters tapped.
{T}: Add {B}.

Malakir Rebirth

Choose target creature. You lose 2 life. Until end of turn, that creature gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Malakir Rebirth // Malakir Mire

Forbidden Orchard

{T}: Add one mana of any color.
Whenever you tap Forbidden Orchard for mana, target opponent creates a 1/1 colorless Spirit creature token.

Mutavault

{T}: Add {C}.
{1}: Mutavault becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Whir of Invention

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

Revel in Riches

Whenever a creature an opponent controls dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
At the beginning of your upkeep, if you control ten or more Treasures, you win the game.

Trinket Mage

When Trinket Mage enters, you may search your library for an artifact card with mana value 1 or less, reveal that card, put it into your hand, then shuffle.

Demonic Tutor

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

Morphic Pool

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

Temple of Deceit

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {B}.

Kormus Bell

All Swamps are 1/1 black creatures that are still lands.

Sudden Spoiling

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Until end of turn, creatures target player controls lose all abilities and have base power and toughness 0/2.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Arcane Signet

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

Sludge Monster

Whenever Sludge Monster enters or attacks, put a slime counter on up to one other target creature.
Non-Horror creatures with slime counters on them lose all abilities and have base power and toughness 2/2.

Spark Double

You may have Spark Double enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Watery Grave

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

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Command Tower

Sakashima of a Thousand Faces

You may have Sakashima of a Thousand Faces enter as a copy of another creature you control, except it has Sakashima of a Thousand Faces's other abilities.
The "legend rule" doesn't apply to permanents you control.
Partner (You can have two commanders if both have partner.)

Phyrexian Metamorph

({U/P} can be paid with either {U} or 2 life.)
You may have Phyrexian Metamorph enter as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.

Mass Diminish

Until your next turn, creatures target player controls have base power and toughness 1/1.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Vedalken Humiliator

Metalcraft — Whenever Vedalken Humiliator attacks, if you control three or more artifacts, creatures your opponents control lose all abilities and have base power and toughness 1/1 until end of turn.

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Lazav, the Multifarious

When Lazav, the Multifarious enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
{X}: Lazav, the Multifarious becomes a copy of target creature card in your graveyard with mana value X, except its name is Lazav, the Multifarious, it's legendary in addition to its other types, and it has this ability.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Flux Channeler

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Damnation

Destroy all creatures. They can't be regenerated.

Dimir Signet

Grim Affliction

Put a -1/-1 counter on target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Gilded Lotus

Phyrexian Tower

{T}: Add {C}.
{T}, Sacrifice a creature: Add {B}{B}.

Arcane Adaptation

As Arcane Adaptation enters, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Glasspool Shore

Glasspool Shore enters tapped.
{T}: Add {U}.

Glasspool Mimic

You may have Glasspool Mimic enter as a copy of a creature you control, except it's a Shapeshifter Rogue in addition to its other types.

Glasspool Mimic // Glasspool Shore

Polymorphist's Jest

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Sol Ring

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Gift of Doom

Enchant creature
Enchanted creature has deathtouch and indestructible.
Morph—Sacrifice another creature. (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
As Gift of Doom is turned face up, you may attach it to a creature.

Reshape

As an additional cost to cast this spell, sacrifice an artifact.
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Clackbridge Troll

Trample, haste
When Clackbridge Troll enters, target opponent creates three 0/1 white Goat creature tokens.
At the beginning of combat on your turn, any opponent may sacrifice a creature of their choice. If a player does, tap Clackbridge Troll, you gain 3 life, and you draw a card.

Thran Dynamo

Tezzeret's Gambit

({U/P} can be paid with either {U} or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Sire of Stagnation

Devoid (This card has no color.)
Whenever a land an opponent controls enters, that player exiles the top two cards of their library and you draw two cards.

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters tapped unless you control two or more basic lands.

Snow-Covered Island

Shapesharer

Changeling (This card is every creature type.)
{2}{U}: Target Shapeshifter becomes a copy of target creature until your next turn.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Infernal Genesis

At the beginning of each player's upkeep, that player mills a card. Then they create X 1/1 black Minion creature tokens, where X is the milled card's mana value.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Massacre Wurm

When this creature enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

Urborg, Tomb of Yawgmoth

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

Toxic Deluge

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