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.

Island

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.

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile Relic of Progenitus: Exile all graveyards. Draw a card.

Mountain

Tempest Harvester

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

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Gorilla Shaman

{X}{X}{1}: Destroy target noncreature artifact with mana value X.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Tune the Narrative

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

Aether Theorist

When Aether Theorist enters, 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.)

Fiery Cannonade

Fiery Cannonade deals 2 damage to each non-Pirate creature.

Aether Chaser

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

Thriving Skyclaw

Flying
When Thriving Skyclaw enters, you get {E}{E}{E} (three energy counters).
Whenever Thriving Skyclaw attacks, you may pay {E}{E}{E}. If you do, put a +1/+1 counter on it.

Prismari Campus

Prismari Campus enters tapped.
{T}: Add {U} or {R}.
{4}, {T}: Scry 1.

Breath Weapon

Breath Weapon deals 2 damage to each non-Dragon creature.

Thriving Grubs

When Thriving Grubs enters, you get {E}{E} (two energy counters).
Whenever Thriving Grubs attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it.

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.

Eroded Canyon

Eroded Canyon enters tapped.
When Eroded Canyon enters, it deals 1 damage to target opponent.
{T}: Add {U} or {R}.

Preordain

Scry 2, then draw a card. (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.)

Thriving Turtle

When Thriving Turtle enters, you get {E}{E} (two energy counters).
Whenever Thriving Turtle attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it.

Flame Slash

Flame Slash deals 4 damage to target creature.

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.