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.

Sower of Discord

Flying
As Sower of Discord enters, choose two players.
Whenever damage is dealt to one of the chosen players, the other chosen player also loses that much life.

Shrivel

All creatures get -1/-1 until end of turn.

Brawler's Plate

Equipped creature gets +2/+2 and has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Opal Palace

{T}: Add {C}.
{1}, {T}: Add one mana of any color in your commander's color identity. If you spend this mana to cast your commander, it enters with a number of additional +1/+1 counters on it equal to the number of times it's been cast from the command zone this game.

Myriad Landscape

Myriad Landscape enters 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.

Without Weakness

Target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it. If its toughness is 0 or less, it's still put into its owner's graveyard.)
Cycling {2} ({2}, Discard this card: Draw a card.)

Murder

Lavaspur Boots

Equipped creature gets +1/+0 and has haste and ward {1}. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)
Equip {1}

Cruel Feeding

Strive — This spell costs {2}{B} more to cast for each target beyond the first.
Any number of target creatures each get +1/+0 and gain lifelink until end of turn. (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Ichor Shade

At the beginning of your end step, if an artifact or creature was put into a graveyard from the battlefield this turn, put a +1/+1 counter on Ichor Shade.

Myr Battlesphere

When Myr Battlesphere enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever Myr Battlesphere attacks, you may tap X untapped Myr you control. If you do, Myr Battlesphere gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Jousting Lance

Equipped creature gets +2/+0.
During your turn, equipped creature has first strike.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Drown in Sorrow

All creatures get -2/-2 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Coat with Venom

Target creature gets +1/+2 and gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Ashnod's Intervention

Until end of turn, target creature gets +2/+0 and gains "When this creature dies or is put into exile from the battlefield, return it to its owner's hand."

Collective Nightmare

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Target creature gets -3/-3 until end of turn.

Revenge of Ravens

Whenever a creature attacks you or a planeswalker you control, that creature's controller loses 1 life and you gain 1 life.

Gorgon's Head

Equipped creature has deathtouch.
Equip {2}

Shield of the Realm

If a source would deal damage to equipped creature, prevent 2 of that damage.
Equip {1}

Blighted Bat

Flying
{1}: Blighted Bat gains haste until end of turn.

Archfiend of Despair

Flying
Your opponents can't gain life.
At the beginning of each end step, each opponent loses life equal to the life that player lost this turn. (Damage causes loss of life.)

Skeletal Grimace

Enchant creature
Enchanted creature gets +1/+1 and has "{B}: Regenerate this creature."

Mukotai Ambusher

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Lifelink

Nightmare

Flying (This creature can't be blocked except by creatures with flying or reach.)
Nightmare's power and toughness are each equal to the number of Swamps you control.

Gilded Pinions

When Gilded Pinions enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Equipped creature has flying.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Bladed Battle-Fan

Flash
When Bladed Battle-Fan enters, attach it to target creature you control. That creature gains indestructible until end of turn.
Equipped creature gets +1/+0.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Blood Reckoning

Whenever a creature attacks you or a planeswalker you control, that creature's controller loses 1 life.

Rise from the Grave

Put target creature card from a graveyard onto the battlefield under your control. That creature is a black Zombie in addition to its other colors and types.

Night's Whisper

Vicious Rumors

Vicious Rumors deals 1 damage to each opponent. Each opponent discards a card, then mills a card. You gain 1 life.

Child of Night

Grotesque Mutation

Target creature gets +3/+1 and gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Stab Wound

Enchant creature
Enchanted creature gets -2/-2.
At the beginning of the upkeep of enchanted creature's controller, that player loses 2 life.

Leather Armor

Equipped creature gets +0/+1 and has ward {1}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)
Equip {0}. Activate only once each turn.

Feast of Succession

All creatures get -4/-4 until end of turn. You become the monarch.

Persistent Specimen

{2}{B}: Return Persistent Specimen from your graveyard to the battlefield tapped.

Yargle, Glutton of Urborg

Unhallowed Pact

Enchant creature
When enchanted creature dies, return that card to the battlefield under your control.

Dying Wish

Enchant creature you control
When enchanted creature dies, target player loses X life and you gain X life, where X is its power.

Costly Plunder

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Asphyxiate

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Dusk Mangler

As an additional cost to cast this spell, sacrifice a creature, discard a card, or pay 4 life.
When Dusk Mangler enters, each opponent sacrifices a creature of their choice, discards a card, and loses 4 life.

Entomb

Search your library for a card, put that card into your graveyard, then shuffle.

Gonti, Lord of Luxury

Deathtouch
When Gonti, Lord of Luxury enters, look at the top four cards of target opponent's library, exile one of them face down, then put the rest on the bottom of that library in a random order. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Gavony Unhallowed

Whenever another creature you control dies, put a +1/+1 counter on Gavony Unhallowed.

Ambuscade Shaman

Whenever Ambuscade Shaman or another creature you control enters, that creature gets +2/+2 until end of turn.
Dash {3}{B} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Ring of Xathrid

{2}: Regenerate equipped creature. (The next time that creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's black.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Demon's Horn

Whenever a player casts a black spell, you may gain 1 life.

Sign in Blood

Target player draws two cards and loses 2 life.

Syphon Soul

Syphon Soul deals 2 damage to each other player. You gain life equal to the damage dealt this way.

Queen's Bay Paladin

Whenever Queen's Bay Paladin enters or attacks, return up to one target Vampire card from your graveyard to the battlefield with a finality counter on it. You lose life equal to its mana value. (If a creature with a finality counter on it would die, exile it instead.)

Tendrils of Corruption

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

Meteor Golem

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

Sol Ring

Spiteful Shadows

Enchant creature
Whenever enchanted creature is dealt damage, it deals that much damage to its controller.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Prying Blade

Equipped creature gets +1/+0.
Whenever equipped creature deals combat damage to a player, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Disciple of Griselbrand

{1}, Sacrifice a creature: You gain life equal to the sacrificed creature's toughness.

Blood for Bones

As an additional cost to cast this spell, sacrifice a creature.
Return a creature card from your graveyard to the battlefield, then return another creature card from your graveyard to your hand.

Wayfarer's Bauble

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

Courier Bat

Flying
When Courier Bat enters, if you gained life this turn, return up to one target creature card from your graveyard to your hand.

Soul Salvage

Return up to two target creature cards from your graveyard to your hand.

Dark Ritual

Jet Medallion

Black spells you cast cost {1} less to cast.

Nezumi Prowler

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When Nezumi Prowler enters, target creature you control gains deathtouch and lifelink until end of turn.

Ichor Drinker

Lifelink
{B}, Exile Ichor Drinker from your graveyard: Incubate 2. Activate only as a sorcery. (Create an Incubator token with two +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Gurgling Anointer

Flying
Whenever you draw your second card each turn, put a +1/+1 counter on Gurgling Anointer.
When Gurgling Anointer dies, return another target creature card with mana value less than or equal to Gurgling Anointer's power from your graveyard to the battlefield.

Night Clubber

When Night Clubber enters, creatures your opponents control get -1/-1 until end of turn.
Blitz {2}{B} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Soul Bleed

Enchant creature
At the beginning of the upkeep of enchanted creature's controller, that player loses 1 life.

Boon of Erebos

Target creature gets +2/+0 until end of turn. Regenerate it. You lose 2 life.

Doomed Dissenter

When Doomed Dissenter dies, create a 2/2 black Zombie creature token.

Rogue's Gloves

Whenever equipped creature deals combat damage to a player, you may draw a card.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Taste of Blood

Taste of Blood deals 1 damage to target player or planeswalker and you gain 1 life.

Reassembling Skeleton

{1}{B}: Return Reassembling Skeleton from your graveyard to the battlefield tapped.

Trespasser's Curse

Enchant player
Whenever a creature enchanted player controls enters, that player loses 1 life and you gain 1 life.

Blessing of Leeches

Flash
Enchant creature
At the beginning of your upkeep, you lose 1 life.
{0}: Regenerate enchanted creature.

Swamp

Kitesail

Equipped creature gets +1/+0 and has flying.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Battle-Rage Blessing

Target creature gains deathtouch and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Giant Scorpion

Mask of Avacyn

Equipped creature gets +1/+2 and has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {3}

The Dross Pits

The Dross Pits enters tapped.
{T}: Add {B}.
{1}{B}, {T}, Sacrifice The Dross Pits: Draw a card.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Doom Blade

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Diamond Mare

As Diamond Mare enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Breach the Multiverse

Each player mills ten cards. For each player, choose a creature or planeswalker card in that player's graveyard. Put those cards onto the battlefield under your control. Then each creature you control becomes a Phyrexian in addition to its other types.

Wander in Death

Return up to two target creature cards from your graveyard to your hand.
Cycling {2} ({2}, Discard this card: Draw a card.)

Defiant Bloodlord

Flying
Whenever you gain life, target opponent loses that much life.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Fell Mire

As Fell Mire enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.

Fell the Profane

Fell the Profane // Fell Mire

Mark of the Vampire

Enchant creature
Enchanted creature gets +2/+2 and has lifelink.

Crypt Incursion

Exile all creature cards from target player's graveyard. You gain 3 life for each card exiled this way.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Memory of Toshiro

{T}, Pay 1 life: Add {B}. Spend this mana only to cast an instant or sorcery spell.

Life of Toshiro Umezawa

(As this Saga enters and after your draw step, add a lore counter.)
I, II — Choose one —
• Target creature gets +2/+2 until end of turn.
• Target creature gets -1/-1 until end of turn.
• You gain 2 life.
III — Exile this Saga, then return it to the battlefield transformed under your control.