Spectator Seating

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

Nahiri's Resolve

Creatures you control get +1/+0 and have haste.
At the beginning of your end step, exile any number of nontoken artifacts and/or creatures you control. Return those cards to the battlefield under their owner's control at the beginning of your next upkeep.

Dictate of Heliod

Jaxis, the Troublemaker

{R}, {T}, Discard a card: Create a token that's a copy of another target creature you control. It gains haste and "When this token dies, draw a card." Sacrifice it at the beginning of the next end step. Activate only as a sorcery.
Blitz {1}{R} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Conduit Goblin

When this creature enters, you get {E}{E} (two energy counters).
At the beginning of combat on your turn, you may pay {E}. If you do, another target creature you control gets +1/+0 and gains haste until end of turn.

Behemoth of Vault 0

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

Blaster Hulk

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.

Hallowed Fountain

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

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

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.

Synth Eradicator

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.

Lightning Runner

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.

Solar Transformer

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.

Voltstorm Angel

Flying
When this creature enters, you get {E}{E}{E} (three energy counters).
At the beginning of combat on your turn, you may pay {E}{E}. When you do, choose one —
• This creature gains vigilance and lifelink until end of turn.
• Other creatures you control get +1/+1 until end of turn.

Arcane Signet

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

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.

Liberty Prime, Recharged

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.

Cayth, Famed Mechanist

Fabricate 1 (When this creature enters, put a +1/+1 counter on it or create a 1/1 colorless Servo artifact creature token.)
Other nontoken creatures you control have fabricate 1.
{2}, {T}: Choose one —
• Populate.
• Proliferate.

Wheel of Potential

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.

Overclocked Electromancer

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.

T-45 Power Armor

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}

Razorfield Ripper

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.)

Electrosiphon

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

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. This land deals 1 damage to you.

Janjeet Sentry

When this creature enters, you get {E}{E} (two energy counters).
{T}, Pay {E}{E}: You may tap or untap target artifact or creature.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Azorius Signet

Sacred Foundry

({T}: Add {R} or {W}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

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.

The Motherlode, Excavator

When The Motherlode 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.

Sentry Bot

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.

Sea of Clouds

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

Aethersquall Ancient

Flying
At the beginning of your upkeep, you get {E}{E}{E} (three energy counters).
Pay eight {E}: Return all other creatures to their owners' hands. Activate only as a sorcery.

Island

Stormcarved Coast

This land enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.

Land Tax

At the beginning of your upkeep, if an opponent controls more lands than you, you may search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Swords to Plowshares

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

Conversion Apparatus

{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.

Crackling Falls

This land enters tapped.
{T}: Add {U} or {R}.

Rush of Inspiration

Draw two cards. Then discard a card at random unless you pay {E}{E} (two energy counters).

Rush of Inspiration // Crackling Falls

Smelted Chargebug

Menace
When this creature enters, you get {E}{E} (two energy counters).
Whenever this creature attacks, you may pay {E}. If you do, another target attacking creature gets +1/+0 and gains menace until end of turn.

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.

Electrozoa

Flash
Flying
When this creature enters, you get {E}{E} (two energy counters).
At the beginning of your first main phase, tap this creature unless you pay {E}.

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.

Aether Chaser

First strike
When this creature enters, you get {E}{E} (two energy counters).
Whenever this creature attacks, you may pay {E}{E}. If you do, create a 1/1 colorless Servo artifact creature token.

Rabble Rousing

Hideaway 5 (When this enchantment enters, look at the top five cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Whenever you attack with one or more creatures, create that many 1/1 green and white Citizen creature tokens. Then if you control ten or more creatures, you may play the exiled card without paying its mana cost.

Orderly Plaza

This land enters tapped.
{T}: Add {W} or {U}.

Suppression Ray

Tap all creatures target player controls. You may pay any amount of {E}. If you do, choose up to that many creatures tapped this way. Put a stun counter on each of them. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Suppression Ray // Orderly Plaza

Boros Charm

Choose one —
• Boros Charm deals 4 damage to target player or planeswalker.
• Permanents you control gain indestructible until end of turn.
• Target creature gains double strike until end of turn.

Multiform Wonder

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

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Spontaneous Artist

When this creature enters, you get {E} (an energy counter).
Pay {E}: Target creature gains haste until end of turn.

Galvanic Discharge

Choose target creature or planeswalker. You get {E}{E}{E} (three energy counters), then you may pay any amount of {E}. Galvanic Discharge deals that much damage to that permanent.

Filigree Racer

When this Vehicle enters, you get {E}{E}{E}{E} (four energy counters).
Whenever this Vehicle attacks, you may pay {E}{E}. When you do, target instant or sorcery card in your graveyard gains jump-start until end of turn. (You may cast that card from your graveyard by discarding a card in addition to paying its other costs. Then exile it.)
Crew 1

Izzet Signet

Fierce Guardianship

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

Hexgold Slith

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

Aether Tradewinds

Return target permanent you control and target permanent you don't control to their owners' hands.

Counterspell

Inventor's Axe

Flash
When this Equipment enters, you get {E}{E} (two energy counters).
When this Equipment enters, attach it to target creature you control.
Equipped creature gets +2/+0.
Equip—Pay {E}{E}.

Plains

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Mystic Monastery

This land enters tapped.
{T}: Add {U}, {R}, or {W}.

Command Tower

Tune the Narrative

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

Aurora Shifter

Whenever this creature deals combat damage to a player, you get that many {E}.
At the beginning of combat on your turn, you may pay {E}{E}. When you do, this creature becomes a copy of another target creature you control, except it has this ability and "Whenever this creature deals combat damage to a player, you get that many {E}."

Spectra Ward

Enchant creature
Enchanted creature gets +2/+2 and has protection from each color. This effect doesn't remove Auras. (It can't be blocked, targeted, or dealt damage by anything that's white, blue, black, red, or green.)

Electrostatic Pummeler

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.

Aethertorch Renegade

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

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Acrobatic Maneuver

Exile target creature you control, then return that card to the battlefield under its owner's control.
Draw a card.

Akroma's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Creatures you control gain flying, vigilance, and double strike until end of turn.
• Creatures you control gain lifelink, indestructible, and protection from each color until end of turn.

Commander's Sphere

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

Lathnu Hellion

Haste
When this creature enters, you get {E}{E} (two energy counters).
At the beginning of your end step, sacrifice this creature unless you pay {E}{E}.

Sol Ring

Emissary of Soulfire

When this creature enters, you get {E}{E}{E} (three energy counters).
Pay {E}{E}: Put an exalted counter on target creature you control. Activate only as a sorcery. (Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

Mountain

Boros Signet

Steam Vents

({T}: Add {U} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Amped Raptor

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.

Volatile Stormdrake

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.

Training Center

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

Molten Duplication

Create a token that's a copy of target artifact or creature you control, except it's an artifact in addition to its other types. It gains haste until end of turn. Sacrifice it at the beginning of the next end step.