Draw cards equal to the number of cards in your hand, then discard a card for each card drawn this way.

Basic landcycling {2} ({2}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

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

Look at the top four cards of your library. Put two of them into your hand and the rest into your graveyard. You lose 2 life.

Hideaway 5 (When this enchantment enters the battlefield, 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.

{T}: Target player mills a card. (They put the top card of their library into their graveyard.)

{5}, {T}, Sacrifice Codex Shredder: Return target card from your graveyard to your hand.

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

Commander creatures you own have menace and "This creature gets +X/+0, where X is the number of creature cards in your graveyard." (A creature with menace can't be blocked except by two or more creatures.)

Cruel Somnophage's power and toughness are each equal to the number of creature cards in all graveyards.

---

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Dakmor Salvage enters the battlefield 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.)

Target creature gets -1/-1 until end of turn.

Dredge 3 (If you would draw a card, you may mill three cards instead. If you do, return this card from your graveyard to your hand.)

Shadow (This creature can block or be blocked by only creatures with shadow.)

If a card would be put into an opponent's graveyard from anywhere, instead exile it with a void counter on it.

{T}, Sacrifice Dauthi Voidwalker: Choose an exiled card an opponent owns with a void counter on it. You may play it this turn without paying its mana cost.

Dimir Aqueduct enters the battlefield tapped.

When Dimir Aqueduct enters the battlefield, return a land you control to its owner's hand.

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

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

Each player mills X cards. For each creature card put into a graveyard this way, you create a tapped 2/2 black Zombie creature token.

When Dreadhound enters the battlefield, mill three cards. (Put the top three cards of your library into your graveyard.)

Whenever a creature dies or a creature card is put into a graveyard from a library, each opponent loses 1 life.

Target player mills three cards.

Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Drowned Catacomb enters the battlefield tapped unless you control an Island or a Swamp.

{T}: Add {U} or {B}.

Flying, trample

When Eater of Days enters the battlefield, you skip your next two turns.

This spell costs {1} less to cast for each artifact you control.

When Emry, Lurker of the Loch enters the battlefield, mill four cards.

{T}: Choose target artifact card in your graveyard. You may cast that card this turn. (You still pay its costs. Timing rules still apply.)

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

Choose target creature. Mill three cards, then put a +1/+1 counter on that creature for each creature card in your graveyard.

Gudul Lurker can't be blocked.

Megamorph {U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Invisible Stalker can't be blocked.

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

Flying, indestructible

Kefnet the Mindful can't attack or block unless you have seven or more cards in hand.

{3}{U}: Draw a card, then you may return a land you control to its owner's hand.

If you would draw a card while your library has no cards in it, you win the game instead.

When Lazav, the Multifarious enters the battlefield, 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.

When Leveler enters the battlefield, exile all cards from your library.

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

Equip {0}

Shadow (This creature can block or be blocked by only creatures with shadow.)

Whenever Looter il-Kor deals damage to an opponent, draw a card, then discard a card.

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

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

{T}: Add {U}.

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

Flying

At the beginning of combat on your turn, each player mills three cards.

Surveil 2, then choose an instant or sorcery card in your graveyard. You may cast it this turn. If that spell would be put into your graveyard, exile it instead. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Morphic Pool enters the battlefield tapped unless you have two or more opponents.

{T}: Add {U} or {B}.

{T}: Add one mana of any color among legendary creatures and planeswalkers you control.

As long as Necrotic Ooze is on the battlefield, it has all activated abilities of all creature cards in all graveyards.

Bestow {2}{B}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)

Nighthowler and enchanted creature each get +X/+X, where X is the number of creature cards in all graveyards.

Surveil 2, then draw two cards. Notion Rain deals 2 damage to you. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Surveil 3. (Look at the top three cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

At the beginning of your upkeep, put two eon counters on Out of the Tombs, then mill cards equal to the number of eon counters on it.

If you would draw a card while your library has no cards in it, instead return a creature card from your graveyard to the battlefield. If you can't, you lose the game.

At the beginning of your end step, put an influence counter on Palantír of Orthanc and scry 2. Then target opponent may have you draw a card. If that player doesn't, you mill X cards, where X is the number of influence counters on Palantír of Orthanc, and that player loses life equal to the total mana value of those cards.

Target player mills three cards.

Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Whenever a land card is put into your graveyard from your library, you may pay {1}. If you do, draw a card.

Trample

When Phyrexian Dreadnought enters the battlefield, sacrifice it unless you sacrifice any number of creatures with total power 12 or greater.

This spell costs {2} less to cast if it targets a legendary creature.

Destroy target creature.

Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Whenever you cast a legendary spell, untap Rona, Herald of Invasion.

{T}: Draw a card, then discard a card.

{5}{B/P}: Transform Rona. Activate only as a sorcery. ({B/P} can be paid with either {B} or 2 life.)

Trample

Whenever a source deals damage to Rona, Tolarian Obliterator, that source's controller exiles a card from their hand at random. If it's a land card, you may put it onto the battlefield under your control. Otherwise, you may cast it without paying its mana cost.

At the beginning of your upkeep, surveil 1. Then if you have seven or more cards in your graveyard, you may transform Search for Azcanta. (Look at the top card of your library. You may put that card into your graveyard.)

(Transforms from Search for Azcanta.)

{T}: Add {U}.

{2}{U}, {T}: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Flash

At the beginning of your upkeep, each player mills three cards. You may exile a creature card from among the cards milled this way. If you do, Shadow Kin becomes a copy of that card, except it has this ability.

Shipwreck Marsh enters the battlefield tapped unless you control two or more other lands.

{T}: Add {U} or {B}.

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

Flying

Whenever Stinkweed Imp deals combat damage to a creature, destroy that creature.

Dredge 5 (If you would draw a card, you may mill five cards instead. If you do, return this card from your graveyard to your hand.)

({T}: Add {U} or {B}.)

Sunken Hollow enters the battlefield tapped unless you control two or more basic lands.

{T}: Add {C}.

{U/B}, {T}: Add {U}{U}, {U}{B}, or {B}{B}.

Defender

{U}: Surge Engine loses defender and gains "This creature can't be blocked."

{2}{U}: Surge Engine becomes blue and has base power and toughness 5/4. Activate only if Surge Engine doesn't have defender.

{4}{U}{U}: Draw three cards. Activate only if Surge Engine is blue and only once.

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

Equipped creature gets +2/+2 and has protection from blue and from black.

Whenever equipped creature deals combat damage to a player, surveil 2. Then you may cast an instant or sorcery spell with mana value 2 or less from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Equip {2}

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.

{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

{T}: Add {B}.

Channel -- {3}{B}, Discard Takenuma, Abandoned Mire: Mill three cards, then return a creature or planeswalker card from your graveyard to your hand. This ability costs {1} less to activate for each legendary creature you control.

{T}: Add {C}.

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

Indestructible

As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

At the beginning of your upkeep, scry 1.

{1}{U}: Target creature you control can't be blocked this turn.

Target player mills two cards.

Draw a card.

Target player mills five cards.

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

When Treacherous Pit-Dweller enters the battlefield from a graveyard, target opponent gains control of it.

Undying (When this creature 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.)

{T}: Add {C}.

{T}: Add {U} or {B}. Underground River deals 1 damage to you.

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

Whenever Urborg Scavengers enters the battlefield or attacks, exile target card from a graveyard. Put a +1/+1 counter on Urborg Scavengers.

Urborg Scavengers has flying as long as a card exiled with it has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

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

{B}: Vector Asp gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Draw a card. If a graveyard has twenty or more cards in it, draw three cards instead.

{T}: Draw a card, then discard a card. If you discarded an instant or sorcery card this way, each opponent loses 1 life and you gain 1 life.

{2}, Sacrifice Vohar, Vodalian Desecrator: You may cast target instant or sorcery card from your graveyard this turn. If that spell would be put into your graveyard, exile it instead. Activate only as a sorcery.

({T}: Add {U} or {B}.)

As Watery Grave enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Hive Mind -- Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.

{1}, {T}: Target player mills three cards.

Choose a Background (You can have a Background as a second commander.)