Impending Doom

Enchant creature
Enchanted creature gets +3/+3 and attacks each combat if able.
When enchanted creature dies, Impending Doom deals 3 damage to that creature's controller.

Drag to the Underworld

This spell costs {X} less to cast, where X is your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
Destroy target creature.

Blight-Breath Catoblepas

When Blight-Breath Catoblepas enters, target creature an opponent controls gets -X/-X until end of turn, where X is your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Lampad of Death's Vigil

{1}, Sacrifice a creature: Each opponent loses 1 life and you gain 1 life.

Venomous Hierophant

Deathtouch
When Venomous Hierophant enters, mill three cards. (Put the top three cards of your library into your graveyard.)

Scavenging Harpy

Flying
When Scavenging Harpy enters, exile target card from an opponent's graveyard.

Incendiary Oracle

{1}{R}: Incendiary Oracle gets +1/+0 until end of turn.
If a creature dealt damage by Incendiary Oracle this turn would die, exile it instead.

Final Flare

As an additional cost to cast this spell, sacrifice a creature or enchantment.
Final Flare deals 5 damage to target creature.

Iroas's Blessing

Enchant creature you control
When Iroas's Blessing enters, it deals 4 damage to target creature or planeswalker an opponent controls.
Enchanted creature gets +1/+1.

Temple of Malice

Temple of Malice enters tapped.
When Temple of Malice enters, scry 1.
{T}: Add {B} or {R}.

Unknown Shores

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Aspect of Lamprey

Enchant creature you control
When Aspect of Lamprey enters, target opponent discards two cards.
Enchanted creature has lifelink.

Inevitable End

Enchant creature
Enchanted creature has "At the beginning of your upkeep, sacrifice a creature."

Mire Triton

Deathtouch
When Mire Triton enters, mill two cards and you gain 2 life. (To mill a card, put the top card of your library into your graveyard.)

Plains

Discordant Piper

When Discordant Piper dies, create a 0/1 white Goat creature token.

Rage-Scarred Berserker

When Rage-Scarred Berserker enters, target creature you control gets +1/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Swamp

Mountain

Kunoros, Hound of Athreos

Vigilance, menace, lifelink
Creature cards in graveyards can't enter the battlefield.
Players can't cast spells from graveyards.

Nightmare Shepherd

Flying
Whenever another nontoken creature you control dies, you may exile it. If you do, create a token that's a copy of that creature, except it's 1/1 and it's a Nightmare in addition to its other types.

Hateful Eidolon

Lifelink
Whenever an enchanted creature dies, draw a card for each Aura you controlled that was attached to it.