Arcane Signet

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

Island

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Gisa and Geralf

When Gisa and Geralf enters, mill four cards.
Once during each of your turns, you may cast a Zombie creature spell from your graveyard.

Rooftop Storm

You may pay {0} rather than pay the mana cost for Zombie creature spells you cast.

Dimir Signet

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Cloudstone Curio

Whenever a nonartifact permanent you control enters, you may return another permanent you control that shares a permanent type with it to its owner's hand.

Sol Ring

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Mind Stone

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

Sedraxis Alchemist

When Sedraxis Alchemist enters, if you control a blue permanent, return target nonland permanent to its owner's hand.

Gravecrawler

Gravecrawler can't block.
You may cast Gravecrawler from your graveyard as long as you control a Zombie.