Choose target spell. You get {E}{E} (two energy counters), then you may pay any amount of {E}. Counter that spell unless its controller pays {1} for each {E} paid this way.

Tap target creature. Metalcraft — If you control three or more artifacts, exile that creature.

Counter target spell. You get an amount of {E} (energy counters) equal to its mana value.

Scry 2, then draw two cards. You get {E}{E} (two energy counters).

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

Draw a card. You get {E}{E} (two energy counters).

If you would get one or more {E} (energy counters), you get twice that many {E} instead. {T}: You get {E}, then you may pay one or more {E}. If you do, create an X/X black Aetherborn creature token, where X is the amount of {E} paid this way.

Whenever a permanent you control is put into a graveyard, you get {E} (an energy counter). {T}, Pay six {E}: Look at the top six cards of your library. You may cast a spell from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

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

Whenever one or more artifact creatures you control deal combat damage to a player, you get {E} (an energy counter). Pay {E}{E}{E}: Create a tapped 3/3 colorless Robot artifact creature token.

{T}: You get {E}{E} (two energy counters). {T}, Pay {E}{E}: Tap target creature. {T}, Pay {E}{E}{E}: Draw a card. Pay {E}{E}{E}{E}: This Vehicle becomes an artifact creature until end of turn. Crew 4

{T}: Add one mana of any color in your commander's color identity. Sacrifice this artifact: Draw a card.

{T}: Add {C}. {3}, {T}: You get {E}{E}{E} (three energy counters). {T}, Pay {E}{E}{E}: Add three mana in any combination of colors.

Whenever a creature you control enters, you get {E} (an energy counter). {4}, {T}: Return target creature you control to its owner's hand.

Whenever an ability of equipped creature is activated, if it isn't a mana ability, copy that ability. You may choose new targets for the copy. Equip {3}

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

Equipped creature gets +1/+1. Whenever equipped creature attacks, you get {E}{E} (two energy counters). Pay {E}{E}: Choose target creature that's blocking equipped creature. Flip a coin. If you win the flip, exile the chosen creature. Otherwise, this Equipment deals 1 damage to it. Equip {2}

This artifact enters tapped. When this artifact enters, you get {E}{E}{E} (three energy counters). {T}: Add {C}. {T}, Pay {E}: Add one mana of any color.

{T}: Add one mana of any color. {1}, {T}: Untap another target artifact. {2}, {T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.) {3}, {T}: Target creature can't be blocked this turn.

Whenever a creature you control attacks, you get {E} (an energy counter). {T}, Pay six {E}: Create a 6/12 colorless Construct artifact creature token with trample. Activate only as a sorcery.

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

When this Equipment enters, you get {E}{E} (two energy counters). Equipped creature gets +3/+3 and doesn't untap during its controller's untap step. At the beginning of your upkeep, you may pay {E}. If you do, untap equipped creature, then put your choice of a menace, trample, or lifelink counter on it. Equip {3}

You have no maximum hand size. {T}: Add {C}.

When this land enters, you get {E} (an energy counter). {T}: Add {C}. {T}, Pay {E}: Add one mana of any color.

This land enters tapped unless you control a Mountain or a Plains. {T}: Add {R} or {W}.

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

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

{T}: Add {C}. {1}, {T}: You get {E} (an energy counter). {3}, {T}, Pay X {E}, Sacrifice this land: Destroy target nonland permanent with mana value X. Activate only as a sorcery.

({T}: Add {U}.)

{T}: Add {C}. {4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

({T}: Add {R}.)

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

{T}: Add {C}. {T}, Sacrifice this land: Search your library for a basic Island, Mountain, or Plains card, put it onto the battlefield tapped, then shuffle. Cycling {U}{R}{W} ({U}{R}{W}, Discard this card: Draw a card.)

({T}: Add {W}.)

({T}: Add {W} or {U}.) This land enters tapped unless you control two or more basic lands.

You have no maximum hand size. {T}: Add {C}.

This land enters tapped unless you have two or more opponents. {T}: Add {W} or {U}.

This land enters tapped unless you have two or more opponents. {T}: Add {R} or {W}.

Whenever this creature attacks, you get {E}{E} (two energy counters). Pay {E}{E}: Exile this creature, then return it to the battlefield under its owner's control.

Flying Whenever this creature or another creature you control enters, you get {E} (an energy counter). Whenever this creature attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it and tap up to one target creature defending player controls.

First strike When this creature enters, you get {E}{E} (two energy counters). Then if you cast it from your hand, exile cards from the top of your library until you exile a nonland card. You may cast that card by paying an amount of {E} equal to its mana value rather than paying its mana cost.

When this creature enters, you get {E}{E} (two energy counters). Whenever an artifact creature you control attacks, you may pay {E}. If you do, put your choice of a +1/+1, first strike, or trample counter on that creature.

This spell costs {1} less to cast for each {E} (energy counter) you've paid or lost this turn. Haste Whenever this creature attacks, you get {E}{E}, then you may pay eight {E}. When you do, this creature deals 8 damage divided as you choose among up to eight targets.

Whenever you cast an artifact spell, you get {E} (an energy counter). {T}, Pay {E}: Target creature gets +1/+0 and gains trample and haste until end of turn. {T}, Pay {E}{E}{E}: Draw a card. {T}, Pay {E}{E}{E}{E}{E}: Return target artifact card from your graveyard to the battlefield tapped.

When this creature enters, you get {E}{E}{E} (three energy counters). Pay {E}{E}{E}: This creature gets +X/+X until end of turn, where X is its power.

Whenever another creature you control enters, you gain 1 life and get {E} (an energy counter). Whenever you attack, you may pay {E}{E}{E}. When you do, put two +1/+1 counters and a flying counter on target attacking creature. It becomes an Angel in addition to its other types.

Vigilance, trample, haste Whenever Liberty Prime attacks or blocks, sacrifice it unless you pay {E}{E} (two energy counters). {2}, {T}, Sacrifice an artifact: You get {E}{E} and draw a card.

Double strike, haste Whenever this creature attacks, you get {E}{E} (two energy counters), then you may pay eight {E}. If you pay, untap all creatures you control, and after this phase, there is an additional combat phase.

At the beginning of combat on your turn, you may pay {E}{E}{E}. If you do, put a +1/+1 counter on this creature. Whenever this creature attacks, double its power until end of turn. Whenever this creature deals combat damage to a creature, if that creature was dealt excess damage this turn, you get X {E}, where X is that excess damage.

Whenever this creature or equipped creature attacks, you get {E} (an energy counter), then it gets +X/+X until end of turn, where X is the amount of {E} you have. Reconfigure—Pay {2} or {E}{E}{E}. (Pay {2} or {E}{E}{E}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Whenever Rex deals combat damage to a player, they mill two cards and you get {E}{E} (two energy counters). Pay {E}{E}: Choose target creature card in a graveyard. Exile it with a brain counter on it. Activate only as a sorcery. Rex has all activated abilities of all cards in exile with brain counters on them.

Flying When this creature enters, you get {E}{E}{E} (three energy counters). Whenever you attack, you may pay {E}{E}. When you do, target creature you control gains lifelink until end of turn.

Robobrain War Mind's power is equal to the number of cards in your hand. When this creature enters, you get an amount of {E} (energy counters) equal to the number of artifact creatures you control. Whenever this creature attacks, you may pay {E}{E}{E}. If you do, draw a card.

Landfall — Whenever a land you control enters, you get {E} (an energy counter). {T}, Pay six {E}: Draw three cards.

Flying, vigilance, trample Whenever you attack, other creatures you control get +2/+2 and gain indestructible until end of turn. Unearth—Pay eight {E}. (Pay eight energy counters: 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.)

Flash This spell costs {1} less to cast for each creature attacking you. When this creature enters, you get {E} for each creature attacking you. At the beginning of combat on your turn, you may pay {E}{E}{E}. If you do, put a +1/+1 counter on each creature you control.

Whenever you attack, you may create a tapped and attacking token that's a copy of target attacking legendary creature you control other than Shaun, except it's not legendary and it's a Synth artifact creature in addition to its other types. When Shaun leaves the battlefield, exile all Synth tokens you control.

When this creature enters, you get {E}{E} (two energy counters). {T}, Pay {E}: Tap target creature.

Flying, lifelink Whenever you gain life, you get that many {E} (energy counters). {W}{U}{U}, {T}, Pay X {E}: Draw X cards.

Haste Whenever this creature attacks, exile the top card of your library. You may get {E}{E} (two energy counters). If you don't, you may play that card this turn. {T}, Pay {E}{E}{E}: This creature deals 3 damage to any target.

Flying, hexproof from activated and triggered abilities When this creature enters, exchange control of this creature and target creature an opponent controls. If you do, you get {E}{E}{E}{E}, then sacrifice that creature unless you pay an amount of {E} equal to its mana value.

Choose target artifact or creature. You get {E}{E}{E}{E} (four energy counters), then you may pay an amount of {E} equal to that permanent's mana value. If you do, gain control of it.

You get {E} (an energy counter), then you may pay one or more {E}. If you do, each creature you control with power equal to the amount of {E} paid this way gains indestructible until end of turn. Destroy all creatures.

({U/P} can be paid with either {U} or 2 life.) Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

You get {E}{E}{E} (three energy counters), then you may pay any amount of {E}. Each player may exile their hand and draw a number of cards equal to the amount of {E} paid this way. If seven or more {E} was paid this way, you may play cards you own exiled this way until the end of your next turn.

Revolt — As long as a permanent left the battlefield under your control this turn, if a source you control would deal noncombat damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead. Whenever you get one or more {E}, this enchantment deals that much damage to any target.

When this enchantment enters, you get {E}{E}{E}{E} (four energy counters). Pay {E}{E}: Prevent all damage that would be dealt to you this turn by a source of your choice.

Whenever an artifact or Artificer you control enters, you may pay {1}. If you do, you get {E}{E} (two energy counters). Pay six {E}, Sacrifice this enchantment: Draw three cards.

When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield. You get {E}{E} (two energy counters). At the beginning of your first main phase, sacrifice this enchantment unless you pay {E}.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I, II — Tap up to one target creature and put a stun counter on it. You get {E}{E} (two energy counters). III — Pay any amount of {E}. If you paid one or more {E} this way, shuffle your library, then exile that many cards from the top. You may play one of those cards without paying its mana cost.