Electrostatic Pummeler

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

Sentry Bot

Flash
This spell costs {1} less to cast for each creature attacking you.
When Sentry Bot 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.

Brotherhood Scribe

Metalcraft — {T}: You get {E} (an energy counter). Activate only if you control three or more artifacts.
Whenever you get one or more {E} during your turn, creatures you control get +1/+1 until end of turn.

Plasma Caster

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, Plasma Caster deals 1 damage to it.
Equip {2}

Behemoth of Vault 0

Trample
When Behemoth of Vault 0 enters, you get {E}{E}{E}{E} (four energy counters).
When Behemoth of Vault 0 dies, you may pay an amount of {E} equal to target nonland permanent's mana value. When you do, destroy that permanent.

The Motherlode, Excavator

When The Motherlode, Excavator enters, choose target opponent. You get an amount of {E} (energy counters) equal to the number of nonbasic lands that player controls.
Whenever The Motherlode attacks, you may pay {E}{E}{E}{E}. When you do, destroy target nonbasic land defending player controls, and creatures that player controls without flying can't block this turn.

Jhoira, Weatherlight Captain

Whenever you cast a historic spell, draw a card. (Artifacts, legendaries, and Sagas are historic.)

Enthusiastic Mechanaut

Flying
Artifact spells you cast cost {1} less to cast.

Glassblower's Puzzleknot

When Glassblower's Puzzleknot enters, scry 2, then you get {E}{E}. (You get two energy counters. To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)
{2}{U}, Sacrifice Glassblower's Puzzleknot: Scry 2, then you get {E}{E}.

Liberty Prime, Recharged

Vigilance, trample, haste
Whenever Liberty Prime, Recharged 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.

Synth Eradicator

Haste
Whenever Synth Eradicator 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}: Synth Eradicator deals 3 damage to any target.

Multiform Wonder

When Multiform Wonder enters, you get {E}{E}{E} (three energy counters).
Pay {E}: Multiform Wonder gains your choice of flying, vigilance, or lifelink until end of turn.
Pay {E}: Multiform Wonder gets +2/-2 or -2/+2 until end of turn.

Etherium Sculptor

Artifact spells you cast cost {1} less to cast.

Dr. Madison Li

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.

HELIOS One

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

Sentinel Sarah Lyons

Haste
As long as an artifact entered the battlefield under your control this turn, creatures you control get +2/+2.
Battalion — Whenever Sentinel Sarah Lyons and at least two other creatures attack, Sentinel Sarah Lyons deals damage equal to the number of artifacts you control to target player.

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Consulate Surveillance

When Consulate Surveillance 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.

Semblance Anvil

Imprint — When Semblance Anvil enters, you may exile a nonland card from your hand.
Spells you cast that share a card type with the exiled card cost {2} less to cast.

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.

Consulate Turret

{T}: You get {E} (an energy counter).
{T}, Pay {E}{E}{E}: Consulate Turret deals 2 damage to target player or planeswalker.

Flux Channeler

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Deadlock Trap

Deadlock Trap enters tapped.
When Deadlock Trap enters, you get {E}{E} (two energy counters).
{T}, Pay {E}: Tap target creature or planeswalker. Its activated abilities can't be activated this turn.

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.

Cloud Key

As Cloud Key enters, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Talisman of Progress

{T}: Add {C}.
{T}: Add {W} or {U}. Talisman of Progress deals 1 damage to you.

T-45 Power Armor

When T-45 Power Armor 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}

Foundry Inspector

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Urza, Lord Protector

Artifact, instant, and sorcery spells you cast cost {1} less to cast.
{7}: If you both own and control Urza, Lord Protector and an artifact named The Mightstone and Weakstone, exile them, then meld them into Urza, Planeswalker. Activate only as a sorcery.

Era of Innovation

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 Era of Innovation: Draw three cards.

Sol Ring

Panharmonicon

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

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.

Robobrain War Mind

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

Ugin, the Ineffable

Colorless spells you cast cost {2} less to cast.
+1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand.
−3: Destroy target permanent that's one or more colors.

Vedalken Archmage

Whenever you cast an artifact spell, draw a card.

Stenn, Paranoid Partisan

As Stenn, Paranoid Partisan enters, choose a card type other than creature or land.
Spells you cast of the chosen type cost {1} less to cast.
{1}{W}{U}: Exile Stenn. Return it to the battlefield under its owner's control at the beginning of the next end step.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Saheeli, Filigree Master

+1: Scry 1. You may tap an untapped artifact you control. If you do, draw a card.
−2: Create two 1/1 colorless Thopter artifact creature tokens with flying. They gain haste until end of turn.
−4: You get an emblem with "Artifact creatures you control get +1/+1" and "Artifact spells you cast cost {1} less to cast."

Starnheim Courser

Flying
Artifact and enchantment spells you cast cost {1} less to cast.

Herald of Kozilek

Devoid (This card has no color.)
Colorless spells you cast cost {1} less to cast.

Whirlwind of Thought

Whenever you cast a noncreature spell, draw a card.

Aethersphere Harvester

Flying
When Aethersphere Harvester enters, you get {E}{E} (two energy counters).
Pay {E}: Aethersphere Harvester gains lifelink until end of turn.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

The Immortal Sun

Players can't activate planeswalkers' loyalty abilities.
At the beginning of your draw step, draw an additional card.
Spells you cast cost {1} less to cast.
Creatures you control get +1/+1.

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Reservoir Walker

When Reservoir Walker enters, you gain 3 life and get {E}{E}{E} (three energy counters).

The Mightstone and Weakstone

When The Mightstone and Weakstone enters, choose one —
• Draw two cards.
• Target creature gets -5/-5 until end of turn.
{T}: Add {C}{C}. This mana can't be spent to cast nonartifact spells.
(Melds with Urza, Lord Protector.)

Aether Hub

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

Electrosiphon

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

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.

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.

Rex, Cyber-Hound

Whenever Rex, Cyber-Hound 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.

Arcane Signet

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

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

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.

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}.