Slobad, Iron Goblin

{T}, Sacrifice an artifact: Add an amount of {R} equal to the sacrificed artifact's mana value. Spend this mana only to cast artifact spells or activate abilities of artifacts.

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

Imskir Iron-Eater

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
When Imskir Iron-Eater enters, you draw X cards and you lose X life, where X is half the number of artifacts you control, rounded down.
{3}{R}, Sacrifice an artifact: Imskir deals damage equal to the sacrificed artifact's mana value to any target.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Illuminor Szeras

Secrets of the Soul — {T}, Sacrifice another creature: Add an amount of {B} equal to the sacrificed creature's mana value.

Rakdos Signet

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Dark Ritual

Arcane Signet

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

Burnt Offering

As an additional cost to cast this spell, sacrifice a creature.
Add X mana in any combination of {B} and/or {R}, where X is the sacrificed creature's mana value.

Talisman of Indulgence

{T}: Add {C}.
{T}: Add {B} or {R}. Talisman of Indulgence deals 1 damage to you.

Sacrifice

As an additional cost to cast this spell, sacrifice a creature.
Add an amount of {B} equal to the sacrificed creature's mana value.

Sol Ring

Mind Stone

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

Soldevi Adnate

{T}, Sacrifice a black or artifact creature: Add an amount of {B} equal to the sacrificed creature's mana value.