Command Tower

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

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik.

Urza's Cave

{T}: Add {C}.
{3}, {T}, Sacrifice this land: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice this land: You may cast spells this turn as though they had flash.

Myriad Landscape

This land enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice this land: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Jet Medallion

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

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Return target artifact card from your graveyard to your hand.