Liquimetal Torque

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

Arcane Signet

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

Mountain

Sol Ring

Urabrask, Heretic Praetor

Haste
At the beginning of your upkeep, exile the top card of your library. You may play it this turn.
At the beginning of each opponent's upkeep, the next time they would draw a card this turn, instead they exile the top card of their library. They may play it this turn.

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Iron Myr

Mind Stone

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

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on Taurean Mauler.

Fellwar Stone

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

Thought Vessel

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