When Blood Fountain enters the battlefield, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")

{3}{B}, {T}, Sacrifice Blood Fountain: Return up to two target creature cards from your graveyard to your hand.

Sacrifice Blood Pet: Add {B}.

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)

I -- You may sacrifice a creature. If you do, each opponent discards a card.

II -- Return target creature card from your graveyard to your hand.

III -- Target opponent may sacrifice a nonland, nontoken permanent. If they don't, they lose 2 life and you draw a card.

{3}, Sacrifice Burnished Hart: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

When Chittering Witch enters the battlefield, create a number of 1/1 black Rat creature tokens equal to the number of opponents you have.

{1}{B}, Sacrifice a creature: Target creature gets -2/-2 until end of turn.

Clay Revenant enters the battlefield tapped.

{2}{B}: Return Clay Revenant from your graveyard to your hand.

Add {B}{B}{B}.

Enchant creature

Enchanted creature gets -2/-0.

When Despondency is put into a graveyard from the battlefield, return Despondency to its owner's hand.

As an additional cost to cast this spell, sacrifice a creature, discard a card, or pay 4 life.

When Dusk Mangler enters the battlefield, each opponent sacrifices a creature, discards a card, and loses 4 life.

Flying

When Marsh Flitter enters the battlefield, create two 1/1 black Goblin Rogue creature tokens.

Sacrifice a Goblin: Marsh Flitter has base power and toughness 3/3 until end of turn.

When Meteor Golem enters the battlefield, destroy target nonland permanent an opponent controls.

Whenever one or more other creatures die, draw a card. This ability triggers only once each turn.

When Mycosynth Wellspring enters the battlefield or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Myriad Landscape enters the battlefield tapped.

{T}: Add {C}.

{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Flying

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Whenever Nefarox, Overlord of Grixis attacks alone, defending player sacrifices a creature.

When Nested Shambler dies, create X tapped 1/1 green Squirrel creature tokens, where X is Nested Shambler's power.

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.

When Nimblewright Schematic enters the battlefield or is put into a graveyard from the battlefield, create a 1/1 colorless Construct artifact creature token.

When Oath of Liliana enters the battlefield, each opponent sacrifices a creature.

At the beginning of each end step, if a planeswalker entered the battlefield under your control this turn, create a 2/2 black Zombie creature token.

Flash

When Omen of the Dead enters the battlefield, return target creature card from your graveyard to your hand.

{2}{B}, Sacrifice Omen of the Dead: Scry 2.

This spell costs {1} less to cast for each creature card in your graveyard.

Exile target creature or planeswalker.

When Phyrexian Delver enters the battlefield, return target creature card from your graveyard to the battlefield. You lose life equal to that card's mana value.

Polluted Mire enters the battlefield tapped.

{T}: Add {B}.

Cycling {2} ({2}, Discard this card: Draw a card.)

When Servo Schematic enters the battlefield or is put into a graveyard from the battlefield, create a 1/1 colorless Servo artifact creature token.

When Sling-Gang Lieutenant enters the battlefield, create two 1/1 red Goblin creature tokens.

Sacrifice a Goblin: Target player loses 1 life and you gain 1 life.

Devoid (This card has no color.)

Flying

At the beginning of your upkeep, sacrifice a creature.

Whenever you sacrifice a creature, draw a card.

When Solemn Simulacrum enters the battlefield, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

When Solemn Simulacrum dies, you may draw a card.

Star Compass enters the battlefield tapped.

{T}: Add one mana of any color that a basic land you control could produce.

Return target creature card with mana value 3 or less from your graveyard to the battlefield.

Cycling {2} ({2}, Discard this card: Draw a card.)

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

When Woe Strider enters the battlefield, create a 0/1 white Goat creature token.

Sacrifice another creature: Scry 1.

Escape--{3}{B}{B}, Exile four other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Woe Strider escapes with two +1/+1 counters on it.

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.