Livaan, Cultist of Tiamat

Whenever you cast a noncreature spell, target creature gets +X/+0 until end of turn, where X is that spell's mana value.
Choose a Background (You can have a Background as a second commander.)

Forest

Mahadi, Emporium Master

At the beginning of your end step, create a Treasure token for each creature that died this turn. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Geode Golem

Trample
Whenever Geode Golem deals combat damage to a player, you may cast your commander from the command zone without paying its mana cost. (You still pay any additional costs.)

Ashen Reaper

Menace
At the beginning of your end step, put a +1/+1 counter on Ashen Reaper if a permanent was put into a graveyard from the battlefield this turn.

Invasion of Azgol

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Azgol enters, target player sacrifices a creature or planeswalker of their choice and loses 1 life.

Invasion of Azgol // Ashen Reaper

Warcry Phoenix

Flying, haste
Whenever you attack with three or more creatures, you may pay {2}{R}. If you do, return Warcry Phoenix from your graveyard to the battlefield tapped and attacking.

Warteye Witch

Whenever Warteye Witch or another creature you control dies, scry 1.

Myr Convert

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
{T}, Pay 2 life: Add one mana of any color.

Moss Diamond

Moss Diamond enters tapped.
{T}: Add {G}.

Gixian Infiltrator

Whenever you sacrifice another permanent, put a +1/+1 counter on Gixian Infiltrator.

Illicit Shipment

Casualty 3 (As you cast this spell, you may sacrifice a creature with power 3 or greater. When you do, copy this spell.)
Search your library for a card, put it into your hand, then shuffle.

Beamtown Beatstick

Equipped creature gets +1/+0 and has menace. (It can't be blocked except by two or more creatures.)
Whenever equipped creature deals combat damage to a player or battle, create a Treasure token.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Boxing Ring

Whenever a creature you control enters, it fights up to one target creature you don't control with the same mana value.
{T}: Create a Treasure token. Activate only if you control a creature that fought this turn.

Glittering Stockpile

{T}: Add {R}. Put a stash counter on Glittering Stockpile.
{T}, Sacrifice Glittering Stockpile: Add X mana of any one color, where X is the number of stash counters on Glittering Stockpile.

Bootleggers' Stash

Lands you control have "{T}: Create a Treasure token."

Fruit of the First Tree

Enchant creature
When enchanted creature dies, you gain X life and draw X cards, where X is its toughness.

Fake Your Own Death

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control and you create a Treasure token." (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Sengir Connoisseur

Flying
Whenever one or more other creatures die, put a +1/+1 counter on Sengir Connoisseur. This ability triggers only once each turn.

Mountain

Golgari Locket

{T}: Add {B} or {G}.
{B/G}{B/G}{B/G}{B/G}, {T}, Sacrifice Golgari Locket: Draw two cards.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Ziatora, the Incinerator

Flying
At the beginning of your end step, you may sacrifice another creature. When you do, Ziatora, the Incinerator deals damage equal to that creature's power to any target and you create three Treasure tokens.

Sol Ring

Slaughter-Priest of Mogis

Whenever you sacrifice a permanent, Slaughter-Priest of Mogis gets +2/+0 until end of turn.
{2}, Sacrifice another creature or an enchantment: Slaughter-Priest of Mogis gains first strike until end of turn.

Evolving Door

{1}, {T}, Sacrifice a creature: Count the colors of the sacrificed creature, then search your library for a creature card that's exactly that many colors plus one. Exile that card, then shuffle. You may cast the exiled card. Activate only as a sorcery.

Blackcleave Cliffs

Blackcleave Cliffs enters tapped unless you control two or fewer other lands.
{T}: Add {B} or {R}.

City on Fire

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.)
If a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Pyre-Sledge Arsonist

{1}, {T}: Pyre-Sledge Arsonist deals X damage to any target, where X is the number of permanents you've sacrificed this turn.

Spike Jester

Gibbering Fiend

When Gibbering Fiend enters, it deals 1 damage to each opponent.
Delirium — At the beginning of each opponent's upkeep, if there are four or more card types among cards in your graveyard, Gibbering Fiend deals 1 damage to that player.

Xorn

If you would create one or more Treasure tokens, instead create those tokens plus an additional Treasure token.

Slime Molding

Quirion Dryad

Whenever you cast a spell that's white, blue, black, or red, put a +1/+1 counter on Quirion Dryad.

Wilderness Reclamation

At the beginning of your end step, untap all lands you control.

Feaster of Fools

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.)
Flying
Devour 2 (As this enters, you may sacrifice any number of creatures. This creature enters with twice that many +1/+1 counters on it.)

Rakdos Cackler

Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

Rakdos Locket

{T}: Add {B} or {R}.
{B/R}{B/R}{B/R}{B/R}, {T}, Sacrifice Rakdos Locket: Draw two cards.

Raphael, Fiendish Savior

Flying
Other Demons, Devils, Imps, and Tieflings you control get +1/+1 and have lifelink.
At the beginning of each end step, if a creature card was put into your graveyard from anywhere this turn, create a 1/1 red Devil creature token with "When this creature dies, it deals 1 damage to any target."

Stormclaw Rager

{1}, Sacrifice another creature or artifact: Put a +1/+1 counter on Stormclaw Rager and draw a card. Activate only as a sorcery.

Riveteers Ascendancy

Whenever you sacrifice a creature, you may return target creature card with lesser mana value from your graveyard to the battlefield tapped. Do this only once each turn.

Kalain, Reclusive Painter

When Kalain, Reclusive Painter enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Other creatures you control enter with an additional +1/+1 counter on them for each mana from a Treasure spent to cast them.

Jungle Hollow

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

Sign in Blood

Target player draws two cards and loses 2 life.

Unmake the Graves

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

Nemesis Phoenix

Flying
{2}{R}: Return Nemesis Phoenix from your graveyard to the battlefield tapped and attacking. Activate only during the declare attackers step and only if you're attacking two or more opponents.

Swamp

Golgari Guildgate

This land enters tapped.
{T}: Add {B} or {G}.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Rakdos Guildgate

This land enters tapped.
{T}: Add {B} or {R}.

Drossforge Bridge

Drossforge Bridge enters tapped.
Indestructible
{T}: Add {B} or {R}.

Showstopper

Until end of turn, creatures you control gain "When this creature dies, it deals 2 damage to target creature an opponent controls."

Footlight Fiend

When Footlight Fiend dies, it deals 1 damage to any target.

Murder

Gut, True Soul Zealot

Whenever you attack, you may sacrifice another creature or an artifact. If you do, create a 4/1 black Skeleton creature token with menace that's tapped and attacking. (It can't be blocked except by two or more creatures.)
Choose a Background (You can have a Background as a second commander.)

Mr. Orfeo, the Boulder

Whenever you attack, double target creature's power until end of turn.

Diabolic Intent

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a card, put that card into your hand, then shuffle.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

The True Scriptures

(As this Saga enters and after your draw step, add a lore counter.)
I — For each opponent, destroy up to one target creature or planeswalker that player controls.
II — Each opponent discards three cards, then mills three cards.
III — Put all creature cards from all graveyards onto the battlefield under your control. Exile The True Scriptures, then return it to the battlefield (front face up).

Sheoldred

Menace
When Sheoldred enters, each opponent sacrifices a nontoken creature or planeswalker of their choice.
{4}{B}: Exile Sheoldred, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery and only if an opponent has eight or more cards in their graveyard.

Sheoldred // The True Scriptures

Unlikely Aid

Target creature gets +2/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Command Tower

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Fain, the Broker

{T}, Sacrifice a creature: Put two +1/+1 counters on target creature.
{T}, Remove a counter from a creature you control: Create a Treasure token.
{T}, Sacrifice an artifact: Create a 2/1 white and black Inkling creature token with flying.
{3}{B}: Untap Fain, the Broker.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Bloodsoaked Altar

{T}, Pay 2 life, Discard a card, Sacrifice a creature: Create a 5/5 black Demon creature token with flying. Activate only as a sorcery.

Riveteers Charm

Choose one —
• Target opponent sacrifices a creature or planeswalker they control with the highest mana value among creatures and planeswalkers they control.
• Exile the top three cards of your library. Until your next end step, you may play those cards.
• Exile target player's graveyard.

Gruul Guildgate

This land enters tapped.
{T}: Add {R} or {G}.

Midnight Reaper

Whenever a nontoken creature you control dies, this creature deals 1 damage to you and you draw a card.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Metalwork Colossus

This spell costs {X} less to cast, where X is the total mana value of noncreature artifacts you control.
Sacrifice two artifacts: Return Metalwork Colossus from your graveyard to your hand.

Mirrodin Avenged

Destroy target creature that was dealt damage this turn.
Draw a card.

Gruul Locket

{T}: Add {R} or {G}.
{R/G}{R/G}{R/G}{R/G}, {T}, Sacrifice Gruul Locket: Draw two cards.

Resourceful Return

Return target creature card from your graveyard to your hand. If you control an artifact, draw a card.

Crew Captain

Haste
Crew Captain has indestructible as long as it entered this turn.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Zurzoth, Chaos Rider

Whenever an opponent draws their first card each turn, if it's not their turn, you create a 1/1 red Devil creature token with "When this creature dies, it deals 1 damage to any target."
Whenever one or more Devils you control attack one or more players, you and those players each draw a card, then discard a card at random.

Gala Greeters

Alliance — Whenever another creature you control enters, choose one that hasn't been chosen this turn —
• Put a +1/+1 counter on Gala Greeters.
• Create a tapped Treasure token.
• You gain 2 life.

Security Rhox

You may pay {R}{G} rather than pay this spell's mana cost. Spend only mana produced by Treasures to cast it this way.