Aether Refinery

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.

Razorfield Ripper

Whenever Razorfield Ripper 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.)

Electrosiphon

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

Tune the Narrative

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

Whirler Virtuoso

When Whirler Virtuoso enters, you get {E}{E}{E} (three energy counters).
Pay {E}{E}{E}: Create a 1/1 colorless Thopter artifact creature token with flying.

Solar Transformer

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

Gonti's Aether Heart

Whenever Gonti's Aether Heart or another artifact you control enters, you get {E}{E} (two energy counters).
Pay eight {E}, Exile Gonti's Aether Heart: Take an extra turn after this one.

Satya, Aetherflux Genius

Menace, haste
Whenever Satya, Aetherflux Genius attacks, create a tapped and attacking token that's a copy of up to one other target nontoken creature you control. You get {E}{E} (two energy counters). At the beginning of the next end step, sacrifice that token unless you pay an amount of {E} equal to its mana value.

Aether Revolt

Revolt — As long as a permanent you controlled left the battlefield 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}, Aether Revolt deals that much damage to any target.

Cyclops Superconductor

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Cyclops Superconductor enters, you get {E}{E}{E} (three energy counters).
When Cyclops Superconductor dies, you may pay {E}{E}{E}. When you do, Cyclops Superconductor deals damage equal to its power to any target.

Sphinx of the Revelation

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

Hexgold Slith

When Hexgold Slith enters, you get {E}{E} (two energy counters).
Whenever Hexgold Slith attacks, you may pay {E}{E}. If you do, it gains first strike until end of turn.
Whenever Hexgold Slith deals combat damage to a player, put a +1/+1 counter on it.

Aethergeode Miner

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

Roil Cartographer

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

Aetherworks Marvel

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.

Lightning Runner

Double strike, haste
Whenever Lightning Runner 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.

Izzet Generatorium

If you would get one or more {E} (energy counters), you get that many plus one {E} instead.
{T}: Draw a card. Activate only if you've paid or lost four or more {E} this turn.

Localized Destruction

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.

Guide of Souls

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.

Stone Idol Generator

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.

Automated Assembly Line

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.

Aetherstorm Roc

Flying
Whenever Aetherstorm Roc or another creature you control enters, you get {E} (an energy counter).
Whenever Aetherstorm Roc 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.

Tempest Harvester

When Tempest Harvester enters, you get {E}{E} (two energy counters).
{T}, Pay {E}: Draw a card, then discard a card.

Wrath of the Skies

You get X {E} (energy counters), then you may pay any amount of {E}. Destroy each artifact, creature, and enchantment with mana value less than or equal to the amount of {E} paid this way.

Fabrication Module

Whenever you get one or more {E} (energy counters), put a +1/+1 counter on target creature you control.
{4}, {T}: You get {E}.

Assaultron Dominator

When Assaultron Dominator 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.

Aethertorch Renegade

When Aethertorch Renegade enters, you get {E}{E}{E}{E} (four energy counters).
{T}, Pay {E}{E}: Aethertorch Renegade deals 1 damage to target creature.
{T}, Pay eight {E}: Aethertorch Renegade deals 6 damage to target player or planeswalker.

Phyrexian Ironworks

Whenever you attack, you get {E} (an energy counter).
{T}, Pay {E}{E}{E}: Create a 3/3 colorless Phyrexian Golem artifact creature token. Activate only as a sorcery.

Aether Spike

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.

Decoction Module

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