As Cloud Key enters the battlefield, choose artifact, creature, enchantment, instant, or sorcery. Spells you cast of the chosen type cost {1} less to cast.

{T}, Sacrifice an artifact: Target player mills three cards. Whenever an artifact enters the battlefield, you may untap Grinding Station.

Sacrifice an artifact: Add {C}{C}.

{T}: Add {U}. {2}{U}: Put an hour counter on Midnight Clock. At the beginning of each upkeep, put an hour counter on Midnight Clock. When the twelfth hour counter is put on Midnight Clock, shuffle your hand and graveyard into your library, then draw seven cards. Exile Midnight Clock.

Imprint — Whenever a nontoken creature dies, you may exile that card. If you do, return each other card exiled with Mimic Vat to its owner's graveyard. {3}, {T}: Create a token that's a copy of a card exiled with Mimic Vat. It gains haste. Exile it at the beginning of the next end step.

{T}: Add {C}. {1}, {T}, Sacrifice Mind Stone: Draw a card.

When Mycosynth Wellspring enters the battlefield or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

You may have Sculpting Steel enter the battlefield as a copy of any artifact on the battlefield.

When The Mightstone and Weakstone enters the battlefield, choose one — • Draw two cards. • Target creature gets -5/-5 until end of turn. {T}: Add {C}{C}. This mana can't be spent to cast nonartifact spells. (Melds with Urza, Lord Protector.)

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

{1}, {T}, Discard a card: You gain 4 life. {1}, {T}, Pay 1 life: Create a 0/1 white Goat creature token. {1}, {T}, Sacrifice a creature: Return target artifact card from your graveyard to your hand. {1}, {T}, Sacrifice an artifact: Draw a card.

Sacrifice an artifact: Put a +1/+1 counter on Arcbound Ravager. Modular 1 (This creature enters the battlefield with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

{T}: Target artifact creature's controller sacrifices it. That player may search their library for a noncreature artifact card, put it onto the battlefield, then shuffle.

You may have Clever Impersonator enter the battlefield as a copy of any nonland permanent on the battlefield.

Each player who has cast a nonartifact spell this turn can't cast additional nonartifact spells.

Artifact spells you cast cost {1} less to cast.

{1}{W}{U}, {T}: Return target artifact or enchantment card from your graveyard to your hand.

Flying When Junk Diver dies, return another target artifact card from your graveyard to your hand.

When Myr Retriever dies, return another target artifact card from your graveyard to your hand.

Magical Tinkering — {W}, {T}, Sacrifice an artifact: Search your library for an artifact card with mana value equal to 1 plus the sacrificed artifact's mana value, put it onto the battlefield, then shuffle. Activate only as a sorcery.

({U/P} can be paid with either {U} or 2 life.) You may have Phyrexian Metamorph enter the battlefield as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.

Commander creatures you own have "{2}, Sacrifice an artifact: Put a +1/+1 counter on this creature and draw a card."

You may have Copy Artifact enter the battlefield as a copy of any artifact on the battlefield, except it's an enchantment in addition to its other types.

You may have Mirrormade enter the battlefield as a copy of any artifact or enchantment on the battlefield.

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

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

{T}: Add {C}. {2}, {T}: Each player draws a card, then discards a card.

Return target artifact card from your graveyard to the battlefield.

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.) Target player takes an extra turn after this one. Return up to one target nonland permanent to its owner's hand. Exile Karn's Temporal Sundering.

Return target artifact card from your graveyard to the battlefield.

As an additional cost to cast this spell, sacrifice an artifact. Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

This spell can't be countered. Destroy all creatures.

Return a creature you control to its owner's hand, then destroy all creatures.