Vile Manifestation

Vile Manifestation gets +1/+0 for each card with cycling in your graveyard.
Cycling {2} ({2}, Discard this card: Draw a card.)

Archfiend of Ifnir

Flying
Whenever you cycle or discard another card, put a -1/-1 counter on each creature your opponents control.
Cycling {2} ({2}, Discard this card: Draw a card.)

Krosan Restorer

{T}: Untap target land.
Threshold — {T}: Untap up to three target lands. Activate only if seven or more cards are in your graveyard.

Far Wanderings

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
Threshold — If seven or more cards are in your graveyard, instead search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

Childhood Horror

Flying
Threshold — As long as seven or more cards are in your graveyard, Childhood Horror gets +2/+2 and can't block.

Forest

Werebear

{T}: Add {G}.
Threshold — Werebear gets +3/+3 as long as seven or more cards are in your graveyard.

Chlorophant

At the beginning of your upkeep, you may put a +1/+1 counter on Chlorophant.
Threshold — As long as seven or more cards are in your graveyard, Chlorophant has "At the beginning of your upkeep, you may put another +1/+1 counter on Chlorophant."

Naturalize

Repentant Vampire

Flying
Whenever a creature dealt damage by Repentant Vampire this turn dies, put a +1/+1 counter on Repentant Vampire.
Threshold — As long as seven or more cards are in your graveyard, Repentant Vampire is white and has "{T}: Destroy target black creature."

Nantuko Blightcutter

Protection from black
Threshold — Nantuko Blightcutter gets +1/+1 for each black permanent your opponents control as long as seven or more cards are in your graveyard.

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Nantuko Husk

Sacrifice a creature: Nantuko Husk gets +2/+2 until end of turn.

Swamp

Decree of Pain

Destroy all creatures. They can't be regenerated. Draw a card for each creature destroyed this way.
Cycling {3}{B}{B} ({3}{B}{B}, Discard this card: Draw a card.)
When you cycle Decree of Pain, all creatures get -2/-2 until end of turn.

Krosan Beast

Threshold — Krosan Beast gets +7/+7 as long as seven or more cards are in your graveyard.

Cabal Initiate

Discard a card: Cabal Initiate gains lifelink until end of turn.
Threshold — Cabal Initiate gets +1/+2 as long as seven or more cards are in your graveyard.

Easy Prey

Destroy target creature with mana value 2 or less.
Cycling {2} ({2}, Discard this card: Draw a card.)

Nimble Mongoose

Shroud (This creature can't be the target of spells or abilities.)
Threshold — Nimble Mongoose gets +2/+2 as long as seven or more cards are in your graveyard.

Possessed Centaur

Trample
Threshold — As long as seven or more cards are in your graveyard, Possessed Centaur gets +1/+1, is black, and has "{2}{B}, {T}: Destroy target green creature."