The Brothers' War

Combat Thresher | Artifact Creature | Construct | Prototype {2}{W} — 1/1 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) Double strike When Combat Thresher enters the battlefield, draw a card. | Victor Harmatiuk

Arcane Proxy | Artifact Creature | Wizard | Prototype {1}{U}{U} — 2/1 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) When Arcane Proxy enters the battlefield, if you cast it, exile target instant or sorcery card with mana value less than or equal to Arcane Proxy's power from your graveyard. Copy that card. You may cast the copy without paying its mana cost. | Kekai Kotaki

Depth Charge Colossus | Artifact Creature | Dreadnought | 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. | Daniel Ljunggren

Hulking Metamorph | Artifact Creature | Shapeshifter | Prototype {2}{U}{U} — 3/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) You may have Hulking Metamorph enter the battlefield as a copy of an artifact or creature you control, except it's an artifact creature in addition to its other types, and its power and toughness are equal to Hulking Metamorph's power and toughness. | Diego Gisbert

Spotter Thopter | Artifact Creature | Thopter | Prototype {3}{U} — 2/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) Flying When Spotter Thopter enters the battlefield, scry X, where X is its power. | Michael Phillippi

Terisian Mindbreaker | Artifact Creature | Juggernaut | 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.) | Steve Prescott

Phyrexian Fleshgorger | Artifact Creature | Phyrexian Wurm | Prototype {1}{B}{B} — 3/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) Menace, lifelink Ward—Pay life equal to Phyrexian Fleshgorger's power. | Steve Prescott

Blitz Automaton | Artifact Creature | Construct | Prototype {2}{R} - 3/2 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) Haste | Simon Dominic

Fallaji Dragon Engine | Artifact Creature | Dragon | Prototype {2}{R} — 1/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) Flying {2}: Fallaji Dragon Engine gets +1/+0 until end of turn. | Filip Burburan

Heavyweight Demolisher | Artifact Creature | Construct | Menace At the beginning of your upkeep, tap Heavyweight Demolisher unless you pay {3}. Unearth {6}{R}{R} ({6}{R}{R}: 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.) | Svetlin Velinov

Skitterbeam Battalion | Artifact Creature | Construct | Prototype {3}{R}{R} — 2/2 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) Trample, haste When Skitterbeam Battalion enters the battlefield, if you cast it, create two tokens that are copies of it. | Leon Tukker

Boulderbranch Golem | Artifact Creature | 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 the battlefield, you gain life equal to its power. | Dan Scott

Iron-Craw Crusher | Artifact Creature | Wurm | Prototype {2}{G}{G} — 2/5 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.) Whenever Iron-Craw Crusher attacks, target attacking creature gets +X/+0 until end of turn, where X is Iron-Craw Crusher's power. | Filip Burburan

Rust Goliath | Artifact Creature | Construct | 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 | Nicholas Gregory

Cityscape Leveler | Artifact Creature | Construct | Trample When you cast this spell and whenever Cityscape Leveler attacks, destroy up to one target nonland permanent. Its controller creates a tapped Powerstone token. Unearth {8} | Leon Tukker

Su-Chi Cave Guard | Artifact Creature | Construct | Vigilance Ward {4} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}.) When Su-Chi Cave Guard dies, add eight {C}. Until end of turn, you don't lose this mana as steps and phases end. | Dmitry Burmak

Terror Ballista | Artifact Creature | Construct | Menace Whenever Terror Ballista attacks, you may sacrifice another creature. When you do, destroy target creature an opponent controls. Unearth {3}{B}{B} ({3}{B}{B}: 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.) | Leon Tukker

Woodcaller Automaton | Artifact Creature | Construct | 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 the battlefield, 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. | Ryan Pancoast