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.

Indestructible As long as your devotion to black is less than five, Erebos isn't a creature. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.) Your opponents can't gain life. {1}{B}, Pay 2 life: Draw a card.

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

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}.

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.

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

({T}: Add {U}.)

({T}: Add {W}.)

({T}: Add {B}.)

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.)

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.

{1}{U}{B}: Whenever a card is put into an opponent's graveyard from anywhere this turn, that player loses 1 life. {2}{U}{B}: Target player mills two 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.

Kicker {3}{U} Each opponent mills eight cards. If this spell was kicked, instead each opponent mills half their library, rounded up.

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

Each opponent reveals cards from the top of their library until they reveal X land cards, then puts all cards revealed this way into their graveyard. X can't be 0.

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

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."

Whenever you draw a card, each opponent mills two cards.

Landfall — Whenever a land you control enters, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Descend 8 — The Ancient One can't attack or block unless there are eight or more permanent cards in your graveyard. {2}{U}{B}: Draw a card, then discard a card. When you discard a card this way, target player mills cards equal to its mana value.

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

At the beginning of your upkeep, you may put a charge counter on this artifact. {T}: You may put a creature card with mana value equal to the number of charge counters on this artifact from your hand onto the battlefield.

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

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 token: Add one mana of any color.")

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

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.")

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

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