Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Blasting Station

{T}, Sacrifice a creature: Blasting Station deals 1 damage to any target.
Whenever a creature enters, you may untap Blasting Station.

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature of their choice.

Entomb

Search your library for a card, put that card into your graveyard, then shuffle.

Myr Moonvessel

Mycosynth Wellspring

When Mycosynth Wellspring enters or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Ashnod's Altar

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Ichor Wellspring

When Ichor Wellspring enters or is put into a graveyard from the battlefield, draw a card.

Summoning Station

{T}: Create a 2/2 colorless Pincher creature token.
Whenever an artifact is put into a graveyard from the battlefield, you may untap Summoning Station.

Merciless Executioner

When Merciless Executioner enters, each player sacrifices a creature of their choice.

Su-Chi

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature of their choice.

Ornithopter

Talisman of Resilience

{T}: Add {C}.
{T}: Add {B} or {G}. Talisman of Resilience deals 1 damage to you.

Executioner's Capsule

{1}{B}, {T}, Sacrifice Executioner's Capsule: Destroy target nonblack creature.

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Dictate of Erebos

Flash
Whenever a creature you control dies, each opponent sacrifices a creature of their choice.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Krark-Clan Ironworks

Sol Ring

Glissa, the Traitor

First strike, deathtouch
Whenever a creature an opponent controls dies, you may return target artifact card from your graveyard to your hand.

Viridian Longbow

Equipped creature has "{T}: This creature deals 1 damage to any target."
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery. This card enters unattached and stays on the battlefield if the creature leaves.)

Salvaging Station

{T}: Return target noncreature artifact card with mana value 1 or less from your graveyard to the battlefield.
Whenever a creature dies, you may untap Salvaging Station.

Arcane Signet

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

Memnite

Ugin, the Ineffable

Colorless spells you cast cost {2} less to cast.
+1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand.
−3: Destroy target permanent that's one or more colors.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Golgari Signet

Demon's Disciple

When Demon's Disciple enters, each player sacrifices a creature or planeswalker of their choice.