You may have Auton Soldier enter the battlefield as a copy of any creature on the battlefield, except it isn't legendary, is an artifact in addition to its other types, and has myriad. (Whenever it attacks, for each opponent other than defending player, you may put a token that's a copy of this creature onto the battlefield tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

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}

You may have Sakashima of a Thousand Faces enter the battlefield 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.)

{T}: Add {C}. {2}, {T}: Each player draws a card, then discards a card.

Flying {T}: Draw a card, then discard a card. {X}: Likeness Looter 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.

{T}: Draw a card, then discard a card. {2}{U}{B}, {T}, Sacrifice Obsessive Stitcher: Return target creature card from your graveyard to the battlefield.

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

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

When Abdel Adrian, Gorion's Ward enters the battlefield, exile any number of other nonland permanents you control until Abdel Adrian leaves the battlefield. Create a 1/1 white Soldier creature token for each permanent exiled this way. Choose a Background (You can have a Background as a second commander.)

When Acererak the Archlich enters the battlefield, if you haven't completed Tomb of Annihilation, return Acererak the Archlich to its owner's hand and venture into the dungeon. Whenever Acererak the Archlich attacks, for each opponent, you create a 2/2 black Zombie creature token unless that player sacrifices a creature.

When Cloister Gargoyle enters the battlefield, venture into the dungeon. (Enter the first room or advance to the next room.) As long as you've completed a dungeon, Cloister Gargoyle gets +3/+0 and has flying.

Flying When Eccentric Apprentice enters the battlefield, venture into the dungeon. (Enter the first room or advance to the next room.) At the beginning of combat on your turn, if you've completed a dungeon, up to one target creature becomes a Bird with base power and toughness 1/1 and flying until end of turn.

Vigilance If a permanent entering the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time. Permanents entering the battlefield don't cause abilities of permanents your opponents control to trigger.

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

Room abilities of dungeons you own trigger an additional time.

Vigilance Whenever Nadaar, Selfless Paladin enters the battlefield or attacks, venture into the dungeon. (Enter the first room or advance to the next room.) Other creatures you control get +1/+1 as long as you've completed a dungeon.

If an artifact or creature entering the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Flying, lifelink Whenever Radiant Solar or another nontoken creature enters the battlefield under your control, venture into the dungeon. (Enter the first room or advance to the next room.) {W}, Discard Radiant Solar: Venture into the dungeon and you gain 3 life.

When Ravenloft Adventurer enters the battlefield, you take the initiative. If a creature an opponent controls would die, instead exile it and put a hit counter on it. Whenever Ravenloft Adventurer attacks, if you've completed a dungeon, defending player loses 1 life for each card they own in exile with a hit counter on it.

Deathtouch When Rilsa Rael, Kingpin enters the battlefield, you take the initiative. Whenever you attack, target attacking creature gains deathtouch until end of turn. If you've completed a dungeon, that creature also gets +5/+0 and gains first strike and menace until end of turn.

When Sarevok's Tome enters the battlefield, you take the initiative. {T}: Add {C}. If you have the initiative, add {C}{C} instead. {3}, {T}: Exile cards from the top of your library until you exile a nonland card. You may cast that card without paying its mana cost. Activate only if you've completed a dungeon.

When Seasoned Dungeoneer enters the battlefield, you take the initiative. Whenever you attack, target attacking Cleric, Rogue, Warrior, or Wizard gains protection from creatures until end of turn. It explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.)

When Tomb of Horrors Adventurer enters the battlefield, you take the initiative. Whenever you cast your second spell each turn, copy it. If you've completed a dungeon, copy that spell twice instead. You may choose new targets for the copies. (A copy of a permanent spell becomes a token.)

When Vicious Battlerager enters the battlefield, you take the initiative. Spiked Retribution — Whenever Vicious Battlerager becomes blocked by a creature, that creature's controller loses 5 life.

Bojuka Bog enters the battlefield tapped. When Bojuka Bog enters the battlefield, exile target player's graveyard. {T}: Add {B}.

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

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

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

({T}: Add {W} or {B}.) As Godless Shrine enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

({T}: Add {W} or {U}.) As Hallowed Fountain enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

({T}: Add {U}.)

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

({T}: Add {W} or {U}.) Meticulous Archive enters the battlefield tapped. When Meticulous Archive enters the battlefield, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

{T}: Add {U}. Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

({T}: Add {W}.)

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

({T}: Add {W}, {U}, or {B}.) Raffine's Tower enters the battlefield tapped. Cycling {3} ({3}, Discard this card: Draw a card.)

{T}: Add {C}. {1}{U}, {T}: Return target Wizard you control to its owner's hand.

({T}: Add {W} or {B}.) Shadowy Backstreet enters the battlefield tapped. When Shadowy Backstreet enters the battlefield, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

{T}: Add {C}. {T}, Sacrifice Strip Mine: Destroy target land.

({T}: Add {B}.)

({T}: Add {U} or {B}.) Undercity Sewers enters the battlefield tapped. When Undercity Sewers enters the battlefield, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

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

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

{T}, Pay 1 life, Sacrifice Scalding Tarn: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

{T}, Pay 1 life, Sacrifice Verdant Catacombs: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

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

When Jirina, Dauntless General enters the battlefield, exile target player's graveyard. Sacrifice Jirina: Humans you control gain hexproof and indestructible until end of turn.

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

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

{T}: Add {W}.

{T}: Add {B}.

Flying {T}: Add one mana of any color.

Enchant creature card in a graveyard When Animate Dead enters the battlefield, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it. Enchanted creature gets -1/-0.

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.

Flying, protection from black Echo {3}{W}{W} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.) When Karmic Guide enters the battlefield, return target creature card from your graveyard to the battlefield.

Each player exiles all creature cards from their graveyard, then sacrifices all creatures they control, then puts all cards they exiled this way onto the battlefield.

Flying When Reveillark leaves the battlefield, return up to two target creature cards with power 2 or less from your graveyard to the battlefield. Evoke {5}{W} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Vigilance Whenever Sun Titan enters the battlefield or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

{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.

Flying When Angel of the Ruins enters the battlefield, exile up to two target artifacts and/or enchantments. Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Flying Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature.

Flash {1}, Sacrifice Cathar Commando: Destroy target artifact or enchantment.

Destroy target creature. A creature destroyed this way can't be regenerated. Overload {2}{W}{W} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Exile target creature. Its controller gains life equal to its power.

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

{T}: Add {C}. {T}, Sacrifice a creature: You gain 1 life.

Sacrifice a creature: Add one mana of any color.

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

Flying Whenever Ancient Brass Dragon deals combat damage to a player, roll a d20. When you do, put any number of target creature cards with total mana value X or less from graveyards onto the battlefield under your control, where X is the result.

Flying Whenever Ancient Gold Dragon deals combat damage to a player, roll a d20. You create a number of 1/1 blue Faerie Dragon creature tokens with flying equal to the result.

Flying Whenever Ancient Silver Dragon deals combat damage to a player, roll a d20. Draw cards equal to the result. You have no maximum hand size for the rest of the game.

Flying Project Image — When Astral Dragon enters the battlefield, create two tokens that are copies of target noncreature permanent, except they're 3/3 Dragon creatures in addition to their other types, and they have flying.

Convoke Flying When Hoarding Broodlord enters the battlefield, search your library for a card, exile it face down, then shuffle. For as long as that card remains exiled, you may play it. Spells you cast from exile have convoke.

Flying When Kokusho, the Evening Star dies, each opponent loses 5 life. You gain life equal to the life lost this way.

Flying Whenever a Dragon you control becomes the target of a spell or ability an opponent controls, destroy target nonland permanent that player controls.

Counter target spell.

Casualty 1 (As you cast this spell, you may sacrifice a creature with power 1 or greater. When you do, copy this spell and you may choose a new target for the copy.) Counter target spell unless its controller pays {2}.

Counter target spell. At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.

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

Whenever you attack, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.") Whenever you sacrifice a Clue, venture into the dungeon. (Enter the first room or advance to the next room.)

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

When Barrowin of Clan Undurr enters the battlefield, venture into the dungeon. (Enter the first room or advance to the next room.) Whenever Barrowin of Clan Undurr attacks, return up to one creature card with mana value 3 or less from your graveyard to the battlefield if you've completed a dungeon.

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.

Dungeon Descent enters the battlefield tapped. {T}: Add {C}. {4}, {T}, Tap an untapped legendary creature you control: Venture into the dungeon. Activate only as a sorcery. (Enter the first room or advance to the next room.)

{T}: Add {C}. {3}, {T}: Venture into the dungeon. Activate only as a sorcery. (Enter the first room or advance to the next room.)

Each opponent loses X life. You gain life equal to the life lost this way.

({T}: Add {W} or {U}.) Prairie Stream enters the battlefield tapped unless you control two or more basic lands.

Flying, hexproof Whenever a Dragon you control attacks, creatures defending player controls get -1/-1 until end of turn.

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

Backup 1 (When this creature enters the battlefield, put a +1/+1 counter on target creature. If that's another creature, it gains the following abilities until end of turn.) Deathtouch Whenever this creature deals combat damage to a player or battle, return target creature card from your graveyard to the battlefield.

Flying, vigilance, indestructible Other permanents you control have indestructible.

Flying, trample Pay 2 life: 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.)

Vigilance Other creatures you control get +2/+2. Creatures your opponents control get -2/-2.

Flying When Magister Sphinx enters the battlefield, target player's life total becomes 10.

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.) At the beginning of your upkeep, return target creature card from your graveyard to the battlefield. At the beginning of each opponent's upkeep, that player sacrifices a creature.

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.