Beseech the Queen

({2/B} can be paid with any two mana or with {B}. This card's mana value is 6.)
Search your library for a card with mana value less than or equal to the number of lands you control, reveal it, put it into your hand, then shuffle.

Go for the Throat

Wight of Precinct Six

This creature gets +1/+1 for each creature card in your opponents' graveyards.

Myr Retriever

When this creature dies, return another target artifact card from your graveyard to your hand.

Dimir Machinations

Look at the top three cards of target player's library. Exile any number of those cards, then put the rest back in any order.
Transmute {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Grinding Station

{T}, Sacrifice an artifact: Target player mills three cards.
Whenever an artifact enters, you may untap this artifact.

Grasp of Darkness

Target creature gets -4/-4 until end of turn.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Heartless Summoning

Creature spells you cast cost {2} less to cast.
Creatures you control get -1/-1.

Gatekeeper of Malakir

Kicker {B} (You may pay an additional {B} as you cast this spell.)
When this creature enters, if it was kicked, target player sacrifices a creature of their choice.