Rakdos Signet

Lhurgoyf

Lhurgoyf's power is equal to the number of creature cards in all graveyards and its toughness is equal to that number plus 1.

Necrogoyf

Necrogoyf's power is equal to the number of creature cards in all graveyards.
At the beginning of each player's upkeep, that player discards a card.
Madness {1}{B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Sol Ring

Gruul Signet

Terravore

Trample
Terravore's power and toughness are each equal to the number of land cards in all graveyards.

Altar of the Goyf

Whenever a creature you control attacks alone, it gets +X/+X until end of turn, where X is the number of card types among cards in all graveyards.
Lhurgoyf creatures you control have trample.

Detritivore

Detritivore's power and toughness are each equal to the number of nonbasic land cards in your opponents' graveyards.
Suspend X—{X}{3}{R}. X can't be 0. (Rather than cast this card from your hand, you may pay {X}{3}{R} and exile it with X time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)
Whenever a time counter is removed from this card while it's exiled, destroy target nonbasic land.

Golgari Signet

Magnivore

Haste (This creature can attack and {T} as soon as it comes under your control.)
Magnivore's power and toughness are each equal to the number of sorcery cards in all graveyards.

Arcane Signet

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

Lightning Greaves

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

Disa the Restless

Whenever a Lhurgoyf permanent card is put into your graveyard from anywhere other than the battlefield, put it onto the battlefield.
Whenever one or more creatures you control deal combat damage to a player, create a Tarmogoyf token.

Mortivore

Mortivore's power and toughness are each equal to the number of creature cards in all graveyards.
{B}: Regenerate this creature. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Tarmogoyf

Tarmogoyf's power is equal to the number of card types among cards in all graveyards and its toughness is equal to that number plus 1.