Millikin

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Goblin Welder

{T}: Choose target artifact a player controls and target artifact card in that player's graveyard. If both targets are still legal as this ability resolves, that player simultaneously sacrifices the artifact and returns the artifact card to the battlefield.

Lorehold Excavation

At the beginning of your end step, mill a card. If a land card was milled this way, you gain 1 life. Otherwise, Lorehold Excavation deals 1 damage to each opponent. (To mill a card, put the top card of your library into your graveyard.)
{5}, Exile a creature card from your graveyard: Create a tapped 3/2 red and white Spirit creature token.

Sol Ring

Tomakul Scrapsmith

When Tomakul Scrapsmith enters, mill three cards. You may put an artifact card from among the cards milled this way into your hand. If you don't, put a +1/+1 counter on Tomakul Scrapsmith. (To mill a card, put the top card of your library into your graveyard.)

Mountain

Song of Blood

Mill four cards. Whenever a creature attacks this turn, it gets +1/+0 until end of turn for each creature card put into your graveyard this way.

Clone Shell

Imprint — When Clone Shell enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom of your library in any order.
When Clone Shell dies, turn the exiled card face up. If it's a creature card, put it onto the battlefield under your control.

Command Tower

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

Ancient Stone Idol

Flash
This spell costs {1} less to cast for each attacking creature.
Trample
When Ancient Stone Idol dies, create a 6/12 colorless Construct artifact creature token with trample.

Desdemona, Freedom's Edge

Vigilance
Whenever Desdemona, Freedom's Edge attacks, target creature card in your graveyard that's an artifact or that has mana value 3 or less gains escape until end of turn. The escape cost is equal to its mana cost plus exile two other cards from your graveyard. (You may cast it from your graveyard for its escape cost this turn.)

Wake the Past

Return all artifact cards from your graveyard to the battlefield. They gain haste until end of turn.

Angel of the Ruins

Flying
When Angel of the Ruins enters, exile up to two target artifacts and/or enchantments.
Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)