Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Kaalia of the Vast

Flying
Whenever Kaalia of the Vast attacks an opponent, you may put an Angel, Demon, or Dragon creature card from your hand onto the battlefield tapped and attacking that opponent.

Shilgengar, Sire of Famine

Flying
Sacrifice another creature: Create a Blood token. If you sacrificed an Angel this way, create a number of Blood tokens equal to its toughness instead.
{W/B}{W/B}{W/B}, Sacrifice six Blood tokens: Return each creature card from your graveyard to the battlefield with a finality counter on it. Those creatures are Vampires in addition to their other types.

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Mountain

Kaalia, Zenith Seeker

Flying, vigilance
When Kaalia, Zenith Seeker enters, look at the top six cards of your library. You may reveal an Angel card, a Demon card, and/or a Dragon card from among them and put them into your hand. Put the rest on the bottom of your library in a random order.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Overpowering Attack

Freerunning {2}{R} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Untap all creatures you control that attacked this turn. If it's your main phase, there is an additional combat phase after this phase, followed by an additional main phase.

Arcane Signet

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

Talisman of Hierarchy

{T}: Add {C}.
{T}: Add {W} or {B}. Talisman of Hierarchy deals 1 damage to you.

Graf Rats

At the beginning of combat on your turn, if you both own and control Graf Rats and a creature named Midnight Scavengers, exile them, then meld them into Chittering Host.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Sulfurous Springs

{T}: Add {C}.
{T}: Add {B} or {R}. Sulfurous Springs deals 1 damage to you.

Bruna, the Fading Light

When you cast this spell, you may return target Angel or Human creature card from your graveyard to the battlefield.
Flying, vigilance
(Melds with Gisela, the Broken Blade.)

Rakdos Carnarium

Rakdos Carnarium enters tapped.
When Rakdos Carnarium enters, return a land you control to its owner's hand.
{T}: Add {B}{R}.

Nomad Outpost

Nomad Outpost enters tapped.
{T}: Add {R}, {W}, or {B}.

Commander's Sphere

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

Phyrexian Dragon Engine

Double strike
When Phyrexian Dragon Engine enters from your graveyard, you may discard your hand. If you do, draw three cards.
Unearth {3}{R}{R}
(Melds with Mishra, Claimed by Gix.)

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Orzhov Basilica

Orzhov Basilica enters tapped.
When Orzhov Basilica enters, return a land you control to its owner's hand.
{T}: Add {W}{B}.

Command Tower

Shattered Landscape

{T}: Add {C}.
{T}, Sacrifice Shattered Landscape: Search your library for a basic Mountain, Plains, or Swamp card, put it onto the battlefield tapped, then shuffle.
Cycling {R}{W}{B} ({R}{W}{B}, Discard this card: Draw a card.)

Aurelia, the Warleader

Flying, vigilance, haste
Whenever Aurelia attacks for the first time each turn, untap all creatures you control. After this phase, there is an additional combat phase.

Boros Signet

Hanweir Battlements

{T}: Add {C}.
{R}, {T}: Target creature gains haste until end of turn.
{3}{R}{R}, {T}: If you both own and control Hanweir Battlements and a creature named Hanweir Garrison, exile them, then meld them into Hanweir, the Writhing Township.

Generous Gift

Destroy target permanent. Its controller creates a 3/3 green Elephant creature token.

Hanweir Garrison

Whenever Hanweir Garrison attacks, create two 1/1 red Human creature tokens that are tapped and attacking.
(Melds with Hanweir Battlements.)

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Blast-Furnace Hellkite

Artifact offering (You may cast this spell as though it had flash by sacrificing an artifact and paying the difference in mana costs between this and the sacrificed artifact. Mana cost includes color.)
Flying, double strike
Creatures attacking your opponents have double strike.

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.)

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Diabolic Tutor

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

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Mortify

Terminate

Destroy target creature. It can't be regenerated.

Isshin, Two Heavens as One

If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Midnight Scavengers

When Midnight Scavengers enters, you may return target creature card with mana value 3 or less from your graveyard to your hand.
(Melds with Graf Rats.)

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Rising of the Day

Creatures you control have haste.
Legendary creatures you control get +1/+0.

Sol Ring

Terramorphic Expanse

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

Drana and Linvala

Flying, vigilance
Activated abilities of creatures your opponents control can't be activated.
Drana and Linvala has all activated abilities of all creatures your opponents control. You may spend mana as though it were mana of any color to activate those abilities.

Boros Garrison

Boros Garrison enters tapped.
When Boros Garrison enters, return a land you control to its owner's hand.
{T}: Add {R}{W}.

Rogue's Passage

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

Talisman of Indulgence

{T}: Add {C}.
{T}: Add {B} or {R}. Talisman of Indulgence deals 1 damage to you.

Drakuseth, Maw of Flames

Flying
Whenever Drakuseth attacks, it deals 4 damage to any target and 3 damage to each of up to two other targets.

Rakdos, Patron of Chaos

Flying, trample
At the beginning of your end step, target opponent may sacrifice two nonland, nontoken permanents of their choice. If they don't, you draw two cards.

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Gisela, Blade of Goldnight

Flying, first strike
If a source would deal damage to an opponent or a permanent an opponent controls, that source deals double that damage to that player or permanent instead.
If a source would deal damage to you or a permanent you control, prevent half that damage, rounded up.

Aurelia, the Law Above

Flying, vigilance, haste
Whenever a player attacks with three or more creatures, you draw a card.
Whenever a player attacks with five or more creatures, Aurelia, the Law Above deals 3 damage to each of your opponents and you gain 3 life.

Sign in Blood

Target player draws two cards and loses 2 life.

Angel of Serenity

Flying
When Angel of Serenity enters, you may exile up to three other target creatures from the battlefield and/or creature cards from graveyards.
When Angel of Serenity leaves the battlefield, return the exiled cards to their owners' hands.

Orzhov Signet

Mishra, Claimed by Gix

Whenever you attack, each opponent loses X life and you gain X life, where X is the number of attacking creatures. If Mishra, Claimed by Gix and a creature named Phyrexian Dragon Engine are attacking, and you both own and control them, exile them, then meld them into Mishra, Lost to Phyrexia. It enters tapped and attacking.

Mind Stone

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

Vault of the Archangel

{T}: Add {C}.
{2}{W}{B}, {T}: Creatures you control gain deathtouch and lifelink until end of turn.

Balefire Dragon

Flying
Whenever Balefire Dragon deals combat damage to a player, it deals that much damage to each creature that player controls.

Arena of Glory

Arena of Glory enters tapped unless you control a Mountain.
{T}: Add {R}.
{R}, {T}, Exert Arena of Glory: Add {R}{R}. If that mana is spent on a creature spell, it gains haste until end of turn. (An exerted permanent won't untap during your next untap step.)

Temple of Silence

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {W} or {B}.

Exotic Orchard

Plains

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.

Bloodgift Demon

Flying
At the beginning of your upkeep, target player draws a card and loses 1 life.

Gisela, the Broken Blade

Flying, first strike, lifelink
At the beginning of your end step, if you both own and control Gisela, the Broken Blade and a creature named Bruna, the Fading Light, exile them, then meld them into Brisela, Voice of Nightmares.