Necrosynthesis

Enchant creature
Enchanted creature has "Whenever another creature dies, put a +1/+1 counter on this creature."
When enchanted creature dies, look at the top X cards of your library, where X is its power. Put one of those cards into your hand and the rest on the bottom of your library in a random order.

Rotting Regisaur

At the beginning of your upkeep, discard a card.

Pandemonium

Whenever a creature enters the battlefield, that creature's controller may have it deal damage equal to its power to any target of their choice.

Chandra's Incinerator

This spell costs {X} less to cast, where X is the total amount of noncombat damage dealt to your opponents this turn.
Trample
Whenever a source you control deals noncombat damage to an opponent, Chandra's Incinerator deals that much damage to target creature or planeswalker that player controls.

Rockfall Vale

Rockfall Vale enters the battlefield tapped unless you control two or more other lands.
{T}: Add {R} or {G}.

Surtland Flinger

Whenever Surtland Flinger attacks, you may sacrifice another creature. When you do, Surtland Flinger deals damage equal to the sacrificed creature's power to any target. If the sacrificed creature was a Giant, Surtland Flinger deals twice that much damage instead.

Mountain

Phyrexian Soulgorger

Cumulative upkeep—Sacrifice a creature. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Thud

As an additional cost to cast this spell, sacrifice a creature.
Thud deals damage equal to the sacrificed creature's power to any target.

Fling

As an additional cost to cast this spell, sacrifice a creature.
Fling deals damage equal to the sacrificed creature's power to any target.

Tend the Pests

As an additional cost to cast this spell, sacrifice a creature.
Create X 1/1 black and green Pest creature tokens with "When this creature dies, you gain 1 life," where X is the sacrificed creature's power.

Momentous Fall

As an additional cost to cast this spell, sacrifice a creature.
You draw cards equal to the sacrificed creature's power, then you gain life equal to its toughness.

Sulfurous Springs

{T}: Add {C}.
{T}: Add {B} or {R}. Sulfurous Springs deals 1 damage to you.

Llanowar Wastes

{T}: Add {C}.
{T}: Add {B} or {G}. Llanowar Wastes deals 1 damage to you.

Savage Lands

Savage Lands enters the battlefield tapped.
{T}: Add {B}, {R}, or {G}.

Daemogoth Titan

Whenever Daemogoth Titan attacks or blocks, sacrifice a creature.

Forest

Soul's Fire

Target creature you control deals damage equal to its power to any target.

Ignoble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {B}, {R}, or {G}.