This spell can't be countered.

You may have Altered Ego enter the battlefield as a copy of any creature on the battlefield, except it enters with X additional +1/+1 counters on it.

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

{T}: Add {C}.

{3}{G}, {T}, Sacrifice Blighted Woodland: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Draw three cards, then put two cards from your hand on top of your library in any order.

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

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

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)

Return target permanent to its owner's hand.

You may have Clever Impersonator enter the battlefield as a copy of any nonland permanent on the battlefield.

You may have Clone enter the battlefield as a copy of any creature on the battlefield.

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

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Counter target spell.

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

You may have Dack's Duplicate enter the battlefield as a copy of any creature on the battlefield, except it has haste and dethrone. (Whenever it attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)

As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Whenever a creature with flying enters the battlefield under your control, it gains haste until end of turn.

Whenever a Dragon enters the battlefield under your control, it deals X damage to any target, where X is the number of Dragons you control.

Whenever a creature with power 3 or greater enters the battlefield under your control, draw a card.

When Eternal Witness enters the battlefield, you may return target card from your graveyard to your hand.

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Creatures you control have haste.

Sacrifice Fires of Yavimaya: Target creature gets +2/+2 until end of turn.

Prevent all combat damage that would be dealt this turn.

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

Frontier Bivouac enters the battlefield tapped.

{T}: Add {G}, {U}, or {R}.

When Garruk's Uprising enters the battlefield, if you control a creature with power 4 or greater, draw a card.

Creatures you control have trample. (They can deal excess combat damage to the player or planeswalker they're attacking.)

Whenever a creature with power 4 or greater enters the battlefield under your control, draw a card.

You may have Gigantoplasm enter the battlefield as a copy of any creature on the battlefield, except it has "{X}: This creature has base power and toughness X/X."

You may have Glasspool Mimic enter the battlefield as a copy of a creature you control, except it's a Shapeshifter Rogue in addition to its other types.

Glasspool Shore enters the battlefield tapped.

{T}: Add {U}.

Draw a card. You may put a land card from your hand onto the battlefield.

Gruul Turf enters the battlefield tapped.

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

{T}: Add {R}{G}.

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}

Permanents you control gain hexproof and indestructible until end of turn.

Hinterland Harbor enters the battlefield tapped unless you control a Forest or an Island.

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

Choose one --

• Destroy target artifact.

• Destroy target enchantment.

• Destroy target artifact and target enchantment.

({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}.)

({T}: Add {U}.)

Izzet Boilerworks enters the battlefield tapped.

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

{T}: Add {U}{R}.

({T}: Add {G}, {U}, or {R}.)

Ketria Triome enters the battlefield tapped.

Cycling {3} ({3}, Discard this card: Draw a card.)

Whenever a creature with power 4 or greater enters the battlefield under your control, draw a card.

-1: Untap target permanent.

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)

Destroy target artifact or enchantment.

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

Equip {0}

You may have Mercurial Pretender enter the battlefield as a copy of a creature you control, except it has "{2}{U}{U}: Return this creature to its owner's hand."

Flying, ward {2}

Whenever another nontoken Dragon enters the battlefield under your control, create a token that's a copy of it, except the token isn't legendary.

The "legend rule" doesn't apply to permanents you control.

Each legendary creature you control gets +1/+1.

Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

You may have Mirror Image enter the battlefield as a copy of a creature you control.

You may have Mirrorhall Mimic enter the battlefield as a copy of any creature on the battlefield, except it's a Spirit in addition to its other types.

Disturb {3}{U}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Enchant creature

At the beginning of your upkeep, create a token that's a copy of enchanted creature, except it's a Spirit in addition to its other types.

If Ghastly Mimicry would be put into a graveyard from anywhere, exile it instead.

({T}: Add {R}.)

({T}: Add {R}.)

({T}: Add {R}.)

({T}: Add {R}.)

Myriad Landscape enters the battlefield tapped.

{T}: Add {C}.

{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

This spell costs {1} less to cast for each land your opponents control that could produce {C}.

Flying

When Obsidian Charmaw enters the battlefield, destroy target nonbasic land an opponent controls.

({U/P} can be paid with either {U} or 2 life.)

You may have Phyrexian Metamorph enter the battlefield as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.

You may have Progenitor Mimic enter the battlefield as a copy of any creature on the battlefield, except it has "At the beginning of your upkeep, if this creature isn't a token, create a token that's a copy of this creature."

You have no maximum hand size.

{T}: Add {C}.

Choose one --

• Draw cards equal to the greatest power among non-Human creatures you control.

• Non-Human creatures you control get +3/+3 until end of turn.

Creature spells you control can't be countered.

Nontoken creatures you control have riot. (They enter the battlefield with your choice of a +1/+1 counter or haste.)

Draw cards equal to the greatest power among creatures you control.

You may cast a spell with mana value 5 or less from your hand without paying its mana cost.

Kicker {5} (You may pay an additional {5} as you cast this spell.)

Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Rootbound Crag enters the battlefield tapped unless you control a Mountain or a Forest.

{T}: Add {R} or {G}.

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.)

You may have Sakashima the Impostor enter the battlefield as a copy of any creature on the battlefield, except its name is Sakashima the Impostor, it's legendary in addition to its other types, and it has "{2}{U}{U}: Return this creature to its owner's hand at the beginning of the next end step."

Flash

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)

You may have Sakashima's Protege enter the battlefield as a copy of any permanent that entered the battlefield this turn.

Ninjutsu {1}{U} ({1}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)

You may have Sakashima's Student enter the battlefield as a copy of any creature on the battlefield, except it's a Ninja in addition to its other creature types.

+1: Creatures you control get +1/+1 and gain haste until end of turn.

-2: Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.

-6: Create five 4/4 red Dragon creature tokens with flying.

Whenever a creature attacks you or a planeswalker you control, each Dragon you control deals 1 damage to that creature.

+1: Until end of turn, each planeswalker you control becomes a 4/4 red Dragon creature and gains flying.

-3: Create a 4/4 red Dragon creature token with flying.

Flying

Whenever Scourge of Valkas or another Dragon enters the battlefield under your control, it deals X damage to any target, where X is the number of Dragons you control.

{R}: Scourge of Valkas gets +1/+0 until end of turn.

Simic Growth Chamber enters the battlefield tapped.

When Simic Growth Chamber enters the battlefield, return a land you control to its owner's hand.

{T}: Add {G}{U}.

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

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

You may have Spark Double enter the battlefield as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

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

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

Create a token that's a copy of target artifact or creature.

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.)

({T}: Add {R} or {G}.)

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

Flash

You may have Stunt Double enter the battlefield as a copy of any creature on the battlefield.

Sulfur Falls enters the battlefield tapped unless you control an Island or a Mountain.

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

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)

Equip {1}

Creatures you control have haste.

Whenever a creature with power 4 or greater enters the battlefield under your control, you may draw a card.

Choose one --

• Target creature you control gets +1/+1 until end of turn. It fights target creature you don't control.

• Counter target spell unless its controller pays {3}.

• Creatures with power 3 or less can't block this turn.

Indestructible

As long as your devotion to blue is less than five, Thassa isn't a creature.

At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.

{3}{U}: Tap another target creature.

You may have Undercover Operative enter the battlefield as a copy of any creature on the battlefield, except it enters with a shield counter on it if you control that creature. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)

As Vesuvan Shapeshifter enters the battlefield or is turned face up, you may choose another creature on the battlefield. If you do, until Vesuvan Shapeshifter is turned face down, it becomes a copy of that creature, except it has "At the beginning of your upkeep, you may turn this creature face down."

Morph {1}{U}

You may have Vizier of Many Faces enter the battlefield as a copy of any creature on the battlefield, except if Vizier of Many Faces was embalmed, the token has no mana cost, it's white, and it's a Zombie in addition to its other types.

Embalm {3}{U}{U}

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Exile target creature. Return it to the battlefield under its owner's control at the beginning of the next end step.

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.)