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.)

Add {B}{B}{B}.

Target player gains control of up to three target nonattacking creatures until end of turn. Untap those creatures. They block this turn if able.

Choose one — • Counter target spell with mana value less than or equal to the number of cards in its controller's graveyard. • Destroy target creature with mana value less than or equal to the number of cards in its controller's graveyard.

Draw two cards, then discard two cards. Untap up to three lands.

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.

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

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

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

{T}: Add one mana of any color. {1}, {T}: Untap target legendary creature you control.

{2}, {T}: Target opponent mills three cards. Put a land card from their graveyard onto the battlefield tapped under your control. It gains "If this land would leave the battlefield, exile it instead of putting it anywhere else." {10}, {T}, Sacrifice Realmbreaker: Search your library for any number of Praetor cards, put them onto the battlefield, then shuffle.

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

{T}: Add {U}. {U}, {T}: Untap target legendary permanent.

Each player mills ten cards. For each player, choose a creature or planeswalker card in that player's graveyard. Put those cards onto the battlefield under your control. Then each creature you control becomes a Phyrexian in addition to its other types.

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Demonstrate (When you cast this spell, you may copy it. If you do, choose an opponent to also copy it.) Mill five cards, then return a creature card from your graveyard to the battlefield.

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.

Replicate—Tap an untapped Horror you control. (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.) Exile target instant or sorcery card from a graveyard and copy it. You may cast the copy without paying its mana cost. Exile Psionic Ritual.

Flash Ward {2} Probing Telepathy — Whenever a creature entering under an opponent's control causes a triggered ability of that creature to trigger, you may copy that ability. You may choose new targets for the copy.

Flying If damage would be dealt to you, prevent that damage and mill twice that many cards.

Arvinox isn't a creature unless you control three or more permanents you don't own. At the beginning of your end step, exile the bottom card of each opponent's library face down. For as long as those cards remain exiled, you may look at them, you may cast permanent spells from among them, and you may spend mana as though it were mana of any color to cast those spells.

Flying At the beginning of your end step, exile the top card of each opponent's library. You may play those cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it. Whenever a nonland permanent an opponent owns enters the battlefield under your control, they lose life equal to its mana value.

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.

Fathomless descent — When this creature enters, target creature an opponent controls gets -X/-X until end of turn, where X is the number of permanent cards in your 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.

Flying When this creature enters, for each opponent, you may cast up to one target instant or sorcery card from that player's graveyard without paying its mana cost. If a spell cast this way would be put into a graveyard, exile it instead.

Menace Whenever this creature attacks a player, exile all cards from that player's hand, then they draw that many cards. You may play lands and cast spells from among the exiled cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.

{T}: You may tap or untap another target permanent. Unearth {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.)

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.

{T}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only during your upkeep.

Flash This spell can't be countered. Whenever you cast a spell, choose up to one — • Return target spell you don't control to its owner's hand. • Return target nonland permanent to its owner's hand.

Trample When this creature enters, target opponent creates two 3/3 green Centaur creature tokens with protection from black.

({B/P} can be paid with either {B} or 2 life.) Lifelink For each {B} in a cost, you may pay 2 life rather than pay that mana. Whenever you cast a black spell, put a +1/+1 counter on K'rrik.

Flash Flying Exploit (When this creature enters, you may sacrifice a creature.) When this creature exploits a creature, counter target spell, activated ability, or triggered ability.

When this creature enters, destroy target creature an opponent controls.

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.) When this creature enters, for each opponent, you may put up to one target creature card from that player's graveyard onto the battlefield under your control.

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.

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

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.

When this creature enters, create a 0/1 white Goat creature token. Sacrifice another creature: Scry 1. Escape—{3}{B}{B}, Exile four other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.) This creature escapes with two +1/+1 counters on it.

Enchant creature {U}: Tap enchanted creature. {U}: Untap enchanted creature.

Creatures don't untap during their controllers' untap steps. Whenever a creature enters, untap all creatures.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I — Each player mills four cards. Then you may exile a creature or planeswalker card from each graveyard. II, III — Until end of turn, you may cast spells from among cards exiled with this Saga, and you may spend mana as though it were mana of any color to cast those spells.

Whenever an opponent casts a spell, that player mills two cards.