Mortivore

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

Nethergoyf

Nethergoyf's power is equal to the number of card types among cards in your graveyard and its toughness is equal to that number plus 1.
Escape—{2}{B}, Exile any number of other cards from your graveyard with four or more card types among them. (You may cast this card from your graveyard for its escape cost.)

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.

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.)

Terravore

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

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.