Involuntary Cooldown

Tap up to two target artifacts and/or creatures. Put two stun counters on each of them. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Island

Terisian Mindbreaker

Whenever Terisian Mindbreaker attacks, defending player mills half their library, rounded up.
Unearth {1}{U}{U}{U} ({1}{U}{U}{U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Cradle Clearcutter

Prototype {2}{G} — 1/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
{T}: Add an amount of {G} equal to Cradle Clearcutter's power.

Argivian Avenger

{1}: Until end of turn, Argivian Avenger gets -1/-1 and gains your choice of flying, vigilance, deathtouch, or haste.

Perennial Behemoth

You may play lands from your graveyard.
Unearth {G}{G} ({G}{G}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Rootwire Amalgam

Prototype {1}{G} — 2/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
{3}{G}{G}, Sacrifice Rootwire Amalgam: Create an X/X colorless Golem artifact creature token, where X is three times Rootwire Amalgam's power. It gains haste until end of turn. Activate only as a sorcery.

Machine Over Matter

This spell costs {1} less to cast if you control an artifact creature.
Return target nonland permanent to its owner's hand.

Woodcaller Automaton

Prototype {2}{G}{G} — 3/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
When Woodcaller Automaton enters, if you cast it, untap target land you control. It becomes a Treefolk creature with haste and base power and toughness equal to Woodcaller Automaton's power and toughness. It's still a land.

Forest

Rust Goliath

Prototype {3}{G}{G} — 3/5 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Reach, trample

Battery Bearer

Creatures you control have "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell."
Whenever you cast an artifact spell with mana value 6 or greater, draw a card.

Stone Retrieval Unit

When Stone Retrieval Unit enters, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Argothian Opportunist

When Argothian Opportunist enters, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Shoot Down

Exile target artifact, enchantment, or creature with flying.

Evolving Wilds

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

Depth Charge Colossus

Prototype {4}{U}{U} — 6/6 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Depth Charge Colossus doesn't untap during your untap step.
{3}: Untap Depth Charge Colossus.

Boulderbranch Golem

Prototype {3}{G} — 3/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
When Boulderbranch Golem enters, you gain life equal to its power.

Fog of War

You gain 1 life for each creature on the battlefield. Prevent all combat damage that would be dealt this turn by creatures with power 3 or less.

Stern Lesson

Draw two cards, then discard a card. Create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Fallaji Excavation

Create three tapped Powerstone tokens. You gain 3 life. (The tokens are artifacts with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Simian Simulacrum

When Simian Simulacrum enters, put two +1/+1 counters on target creature you control.
Unearth {2}{G}{G} ({2}{G}{G}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Mask of the Jadecrafter

{X}, {T}, Sacrifice Mask of the Jadecrafter: Create an X/X colorless Golem artifact creature token. Activate only as a sorcery.
Unearth {2}{G} ({2}{G}: Return this card from your graveyard to the battlefield. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)