Severed Strands

As an additional cost to cast this spell, sacrifice a creature.
You gain life equal to the sacrificed creature's toughness. Destroy target creature an opponent controls.

Martyr of Dusk

When Martyr of Dusk dies, create a 1/1 white Vampire creature token with lifelink.

Hunted Witness

When Hunted Witness dies, create a 1/1 white Soldier creature token with lifelink.

Ajani's Pridemate

Whenever you gain life, put a +1/+1 counter on this creature.

Scoured Barrens

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {B}.

Cruel Celebrant

Whenever Cruel Celebrant or another creature or planeswalker you control dies, each opponent loses 1 life and you gain 1 life.

Dusk Legion Zealot

When Dusk Legion Zealot enters, you draw a card and you lose 1 life.

Oni Possession

Enchant creature
At the beginning of your upkeep, sacrifice a creature.
Enchanted creature gets +3/+3 and has trample.
Enchanted creature is a Demon Spirit.

Secluded Steppe

Secluded Steppe enters tapped.
{T}: Add {W}.
Cycling {W} ({W}, Discard this card: Draw a card.)

Oketra's Monument

White creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, create a 1/1 white Warrior creature token with vigilance.

Swamp

Ulcerate

Target creature gets -3/-3 until end of turn. You lose 3 life.

Vampire Aristocrat

Sacrifice a creature: Vampire Aristocrat gets +2/+2 until end of turn.

Sacred Cat

Lifelink
Embalm {W} ({W}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a white Zombie Cat with no mana cost. Embalm only as a sorcery.)