Attune with Aether

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. You get {E}{E} (two energy counters).

Live Fast

You draw two cards, lose 2 life, and get {E}{E} (two energy counters).

Servant of the Conduit

When Servant of the Conduit enters the battlefield, you get {E}{E} (two energy counters).
{T}, Pay {E}: Add one mana of any color.

Demon of Dark Schemes

Flying
When Demon of Dark Schemes enters the battlefield, all other creatures get -2/-2 until end of turn.
Whenever another creature dies, you get {E} (an energy counter).
{2}{B}, Pay {E}{E}{E}{E}: Put target creature card from a graveyard onto the battlefield under your control tapped.

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Aethertide Whale

Flying
When Aethertide Whale enters the battlefield, you get six {E} (energy counters).
Pay {E}{E}{E}{E}: Return Aethertide Whale to its owner's hand.

Animation Module

Whenever one or more +1/+1 counters are put on a permanent you control, you may pay {1}. If you do, create a 1/1 colorless Servo artifact creature token.
{3}, {T}: Choose a counter on target permanent or player. Give that permanent or player another counter of that kind.

Sylvan Library

At the beginning of your draw step, you may draw two additional cards. If you do, choose two cards in your hand drawn this turn. For each of those cards, pay 4 life or put the card on top of your library.

Disappearing Act

As an additional cost to cast this spell, return a permanent you control to its owner's hand.
Counter target spell.

Gonti's Machinations

Whenever you lose life for the first time each turn, you get {E}. (You get an energy counter. Damage causes loss of life.)
Pay {E}{E}, Sacrifice Gonti's Machinations: Each opponent loses 3 life. You gain life equal to the life lost this way.

Sage of Shaila's Claim

When Sage of Shaila's Claim enters the battlefield, you get {E}{E}{E} (three energy counters).

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.

Evolution Sage

Landfall — Whenever a land enters the battlefield under your control, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Winding Constrictor

If one or more counters would be put on an artifact or creature you control, that many plus one of each of those kinds of counters are put on that permanent instead.
If you would get one or more counters, you get that many plus one of each of those kinds of counters instead.

Greenbelt Rampager

When Greenbelt Rampager enters the battlefield, pay {E}{E} (two energy counters). If you can't, return Greenbelt Rampager to its owner's hand and you get {E}.

Guardian Project

Whenever a nontoken creature enters the battlefield under your control, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Forest

Overgrown Tomb

({T}: Add {B} or {G}.)
As Overgrown Tomb enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Decoction Module

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

Steady Progress

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Opulent Palace

Opulent Palace enters the battlefield tapped.
{T}: Add {B}, {G}, or {U}.

Fierce Guardianship

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

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.)

Aethersphere Harvester

Flying
When Aethersphere Harvester enters the battlefield, 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.)

Reservoir Walker

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

Highspire Infusion

Target creature gets +3/+3 until end of turn. You get {E}{E} (two energy counters).

Architect of the Untamed

Landfall — Whenever a land enters the battlefield under your control, you get {E} (an energy counter).
Pay eight {E}: Create a 6/6 colorless Beast artifact creature token.

Viral Drake

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Cultivate

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.

Inexorable Tide

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

Gonti's Aether Heart

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

Reclamation Sage

When Reclamation Sage enters the battlefield, you may destroy target artifact or enchantment.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters the battlefield tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Die Young

Choose target creature. You get {E}{E} (two energy counters), then you may pay any amount of {E}. The creature gets -1/-1 until end of turn for each {E} paid this way.

Tezzeret's Gambit

({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.)

Glint-Sleeve Siphoner

Menace
Whenever Glint-Sleeve Siphoner enters the battlefield or attacks, you get {E} (an energy counter).
At the beginning of your upkeep, you may pay {E}{E}. If you do, you draw a card and you lose 1 life.

Elvish Mystic

Contagion Clasp

When Contagion Clasp enters the battlefield, put a -1/-1 counter on target creature.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Peema Aether-Seer

When Peema Aether-Seer enters the battlefield, you get an amount of {E} (energy counters) equal to the greatest power among creatures you control.
Pay {E}{E}{E}: Target creature blocks this turn if able.

Birds of Paradise

Merfolk Skydiver

Flying
When Merfolk Skydiver enters the battlefield, put a +1/+1 counter on target creature you control.
{3}{G}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Sol Ring

Shipwreck Moray

When Shipwreck Moray enters the battlefield, you get {E}{E}{E}{E} (four energy counters).
Pay {E}: Shipwreck Moray gets +2/-2 until end of turn.

Exotic Orchard

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

Island

Confiscation Coup

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.

Aether Swooper

Flying
When Aether Swooper enters the battlefield, you get {E}{E} (two energy counters).
Whenever Aether Swooper attacks, you may pay {E}{E}. If you do, create a 1/1 colorless Servo artifact creature token.

Terramorphic Expanse

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

Aether Theorist

When Aether Theorist enters the battlefield, you get {E}{E}{E} (three energy counters).
{T}, Pay {E}: Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

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}.

Rogue Refiner

When Rogue Refiner enters the battlefield, draw a card and you get {E}{E} (two energy counters).

Eternal Witness

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

Aether Hub

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

Empyreal Voyager

Flying, trample
Whenever Empyreal Voyager deals combat damage to a player, you get that many {E} (energy counters).

Glassblower's Puzzleknot

When Glassblower's Puzzleknot enters the battlefield, 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 of your library and the rest on top in any order.)
{2}{U}, Sacrifice Glassblower's Puzzleknot: Scry 2, then you get {E}{E}.

Karn's Bastion

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

Kodama's Reach

Glimmer of Genius

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

Fabled Passage

{T}, Sacrifice Fabled Passage: 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.

Aether Poisoner

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Aether Poisoner enters the battlefield, you get {E}{E} (two energy counters).
Whenever Aether Poisoner attacks, you may pay {E}{E}. If you do, create a 1/1 colorless Servo artifact creature token.

Llanowar Elves

Breeding Pool

({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.

Bojuka Bog

Bojuka Bog enters the battlefield tapped.
When Bojuka Bog enters the battlefield, exile target player's graveyard.
{T}: Add {B}.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Contentious Plan

Counterspell

Aetherwind Basker

Trample
Whenever Aetherwind Basker enters the battlefield or attacks, you get {E} (an energy counter) for each creature you control.
Pay {E}: Aetherwind Basker gets +1/+1 until end of turn.

Yarok, the Desecrated

Deathtouch, lifelink
If a permanent entering the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Evolving Wilds

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

Reliquary Tower

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

Aether Meltdown

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature or Vehicle
When Aether Meltdown enters the battlefield, you get {E}{E} (two energy counters).
Enchanted creature gets -4/-0.

Consulate Turret

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

Swamp

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.

Deadlock Trap

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

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Dynavolt Tower

Whenever you cast an instant or sorcery spell, you get {E}{E} (two energy counters).
{T}, Pay {E}{E}{E}{E}{E}: Dynavolt Tower deals 3 damage to any target.

Era of Innovation

Whenever an artifact or Artificer enters the battlefield under your control, you may pay {1}. If you do, you get {E}{E} (two energy counters).
Pay six {E}, Sacrifice Era of Innovation: Draw three cards.

Shielded Aether Thief

Flash (You may cast this spell any time you could cast an instant.)
Whenever Shielded Aether Thief blocks, you get {E} (an energy counter).
{T}, Pay {E}{E}{E}: Draw a card.

Command Tower

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

Woodweaver's Puzzleknot

When Woodweaver's Puzzleknot enters the battlefield, you gain 3 life and get {E}{E}{E} (three energy counters).
{2}{G}, Sacrifice Woodweaver's Puzzleknot: You gain 3 life and get {E}{E}{E}.