Blightsteel Colossus

Trample, infect, indestructible
If Blightsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.

Etherium Sculptor

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

Silver Myr

Slagstone Refinery

Whenever Slagstone Refinery or another nontoken artifact you control is put into a graveyard from the battlefield or is put into exile from the battlefield, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Urza, Prince of Kroog

Artifact creatures you control get +2/+2.
{6}: Create a token that's a copy of target artifact you control, except it's a 1/1 Soldier creature in addition to its other types.

Foundry Inspector

Energy Refractor

When Energy Refractor enters, draw a card.
{2}: Add one mana of any color.

Shimmer Myr

Flash
You may cast artifact spells as though they had flash.

Plains

Island

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Krark-Clan Ironworks

Azorius Signet

Gold Myr

Ashnod's Altar

Shorikai, Genesis Engine

{1}, {T}: Draw two cards, then discard a card. Create a 1/1 colorless Pilot creature token with "This creature crews Vehicles as though its power were 2 greater."
Crew 8 (Tap any number of creatures you control with total power 8 or more: This Vehicle becomes an artifact creature until end of turn.)
Shorikai, Genesis Engine can be your commander.

Sol Ring

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)