Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Drown in Filth

Choose target creature. Mill four cards, then that creature gets -1/-1 until end of turn for each land card in your graveyard.

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Wailing Ghoul

When Wailing Ghoul enters the battlefield, mill two cards.

Returned Centaur

When Returned Centaur enters the battlefield, target player mills four cards.

Gorging Vulture

Flying
When Gorging Vulture enters the battlefield, mill four cards. You gain 1 life for each creature card milled this way. (To mill four cards, put the top four cards of your library into your graveyard.)

Mountain

Forest

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Returned Reveler

When Returned Reveler dies, each player mills three cards.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Polluted Mire

Polluted Mire enters the battlefield tapped.
{T}: Add {B}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Crow of Dark Tidings

Flying
When Crow of Dark Tidings enters the battlefield or dies, mill two cards. (Put the top two cards of your library into your graveyard.)

Glowspore Shaman

When Glowspore Shaman enters the battlefield, mill three cards. You may put a land card from your graveyard on top of your library. (To mill a card, put the top card of your library into your graveyard.)

Swamp

Songs of the Damned

Add {B} for each creature card in your graveyard.

Entropic Decay

Mill four cards. (Then exile this card. You may cast the creature later from exile.)

Gray Slaad

As long as there are four or more creature cards in your graveyard, Gray Slaad has menace and deathtouch.

Gray Slaad // Entropic Decay

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)