Dark Ritual

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Shipwreck Marsh

This land enters tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. This artifact deals 1 damage to you.

Singularity Rupture

Destroy all creatures, then any number of target players each mill half their library, rounded down.

Emet-Selch of the Third Seat

Spells you cast from your graveyard cost {2} less to cast.
Whenever one or more opponents lose life, you may cast target instant or sorcery card from your graveyard. If that spell would be put into your graveyard, exile it instead. Do this only once each turn.

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. This land deals 1 damage to you.

Hades, Sorcerer of Eld

Vigilance
Echo of the Lost — During your turn, you may play cards from your graveyard.
If a card or token would be put into your graveyard from anywhere, exile it instead.

Emet-Selch, Unsundered

Vigilance
Whenever Emet-Selch enters or attacks, draw a card, then discard a card.
At the beginning of your upkeep, if there are fourteen or more cards in your graveyard, you may transform Emet-Selch.

Emet-Selch, Unsundered // Hades, Sorcerer of Eld

Dimir Signet

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Consuming Aberration

Consuming Aberration's power and toughness are each equal to the number of cards in your opponents' graveyards.
Whenever you cast a spell, each opponent reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Choked Estuary

As this land enters, you may reveal an Island or Swamp card from your hand. If you don't, this land enters tapped.
{T}: Add {U} or {B}.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Arcane Signet

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

Command Tower

Watery Grave

({T}: Add {U} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to that card's mana value.

Dimir Aqueduct

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Counterspell

Morphic Pool

This land enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Drowned Catacomb

This land enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.