Commander creatures you own have "Whenever this creature becomes tapped, it and other creatures you control that share a creature type with it each get +2/+0 and gain undying until end of turn." (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

+2: Draw a card. Each player mills two cards. −5: Put target creature card from a graveyard onto the battlefield under your control. −11: Gain control of all creatures target opponent controls.

Whenever a creature you control becomes blocked, you may return it to its owner's hand. Whenever one or more creatures you control deal combat damage to a player, draw a card.

Flying {T}: Draw a card, then discard a card. {X}: This creature becomes a copy of target creature card in your graveyard with mana value X, except it has flying and this ability. Activate only as a sorcery.

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

This land enters tapped. When this land enters, exile target player's graveyard. {T}: Add {B}.

As this land enters, you may reveal an Island or Swamp card from your hand. If you don't, this land enters tapped. {T}: Add {U} or {B}.

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

This land enters tapped. {T}: Add {B}. Dredge 2 (If you would draw a card, you may mill two cards instead. If you do, return this card from your graveyard to your hand.)

This land enters tapped. When this land enters, return a land you control to its owner's hand. {T}: Add {U}{B}.

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

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

{T}: Add {C}. {3}: Return this card from your graveyard to the battlefield tapped.

({T}: Add {U}.)

This land enters tapped. {T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

{T}: Add {C}. {4}, {T}: Target creature can't be blocked this turn.

This land enters tapped unless you control two or more other lands. {T}: Add {U} or {B}.

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

({T}: Add {B}.)

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

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}.

As Three Tree City enters, choose a creature type. {T}: Add {C}. {2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

{T}: Add {C}. {2}, {T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Whenever another permanent you control enters, each opponent mills a card.

If an opponent would mill one or more cards, they mill twice that many cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Horrors you control have menace. Whenever a Horror you control deals combat damage to a player, that player mills that many cards. At the beginning of your end step, choose target artifact or creature card in an opponent's graveyard that was put there from their library this turn. Put it onto the battlefield under your control.

Consuming Aberration's power and toughness are each equal to the number of cards in your opponents' graveyards. Whenever you cast a spell, each opponent reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Whenever one or more cards are put into your graveyard from your library, this creature gets +1/+1 until end of turn and can't be blocked this turn. {1}{U}{B}: Mill a card.

At the beginning of each player's upkeep, that player mills X cards, where X is the number of cards in their hand.

Each opponent mills fourteen cards. Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.) When you cycle this card, each opponent mills four cards.

Enchant player At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

{T}: Each player mills a card.

Target player mills ten cards.

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.) Whenever this creature attacks and isn't blocked, defending player loses 1 life for each card in their graveyard.

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Whenever this creature attacks, defending player mills ten cards.

{T}: Mill two cards. {2}, Exile this artifact: Shuffle any number of target cards from your graveyard into your library.

Indestructible As long as your devotion to blue and black is less than seven, Phenax isn't a creature. Creatures you control have "{T}: Target player mills X cards, where X is this creature's toughness."

As this creature enters, choose a player. Sewer Nemesis's power and toughness are each equal to the number of cards in the chosen player's graveyard. Whenever the chosen player casts a spell, that player mills a card.

Whenever you draw a card, target opponent mills two cards. If two nonland cards that share a color were milled this way, repeat this process. {5}{U}: Draw a card, then discard a card.

Whenever this creature attacks, defending player mills half their library, rounded up. Unearth {1}{U}{U}{U} ({1}{U}{U}{U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Uchuulon's power is equal to the number of Crabs, Oozes, and/or Horrors you control. Horrific Symbiosis — At the beginning of your end step, exile up to one target creature card from an opponent's graveyard. If you do, create a token that's a copy of this creature.

Umbris gets +1/+1 for each card your opponents own in exile. Whenever Umbris or another Nightmare or Horror you control enters, target opponent exiles cards from the top of their library until they exile a land card.

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

Flash Indestructible When Mithril Coat enters, attach it to target legendary creature you control. Equipped creature has indestructible. Equip {3}

{U/P}: Change a target of target spell or ability to this creature. ({U/P} can be paid with either {U} or 2 life.)

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.)

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

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

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}.

{1}, {T}: Add {U}{B}.

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

Aberrant Tinkering — When this creature enters and at the beginning of your upkeep, each Horror you control gains all activated abilities of target artifact an opponent controls until end of turn. You may spend blue mana as though it were mana of any color to activate those abilities.

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

{T}: Add {C}. {1}, {T}, Sacrifice this artifact: Draw a card.

As this artifact enters, choose a creature type. Creatures you control of the chosen type get +1/+1. {T}: Add one mana of any color.

{T}: Add {C}{C}.

{T}: Add {C}. {T}: Add {U} or {B}. This artifact deals 1 damage to you.

Hideaway 5 (When this enchantment enters, look at the top five cards of your library, exile one face down, then put the rest on the bottom in a random order.) At the beginning of your upkeep, you may mill three cards. Then if there are twenty or more cards in your graveyard, you may play the exiled card without paying its mana cost.

Mill three cards, then you may return a creature card from your graveyard to your hand. (To mill three cards, put the top three cards of your library into your graveyard.)

Return target creature card from your graveyard to the battlefield. Flashback—Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

When this creature dies, put target creature card from your graveyard on top of your library. Dredge 4 (If you would draw a card, you may mill four cards instead. If you do, return this card from your graveyard to your hand.)

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Counter target spell. If that spell targets a commander you control, instead counter that spell, scry 2, then draw a card.

Counter target spell.

Counter target spell unless its controller pays {1} for each card in your graveyard. Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Counter target spell. Its controller mills three cards.

Counter target noncreature spell.

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

Whenever this creature 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.

When this artifact enters, exile target card from a graveyard. {T}, Sacrifice this artifact: Exile each opponent's graveyard. {1}, {T}, Sacrifice this artifact: Draw a card.