Each opponent gets a poison counter. Then each creature your opponents control gets -1/-1 until end of turn for each poison counter its controller has.

{2}, {T}, Sacrifice Expedition Map: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Shadow (This creature can block or be blocked by only creatures with shadow.) If a card would be put into an opponent's graveyard from anywhere, instead exile it with a void counter on it. {T}, Sacrifice Dauthi Voidwalker: Choose an exiled card an opponent owns with a void counter on it. You may play it this turn without paying its mana cost.

Flash You control your opponents while they're searching their libraries. While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.

Deathtouch Whenever you draw a card, you gain 2 life. Whenever an opponent draws a card, they lose 2 life.

Flying Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) {B}: Skithiryx, the Blight Dragon gains haste until end of turn. {B}{B}: Regenerate Skithiryx.

Deathtouch Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) When Ichor Rats enters the battlefield, each player gets a poison counter.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) Whenever Ichorclaw Myr becomes blocked, it gets +2/+2 until end of turn.

You draw two cards and you lose 2 life. Each opponent gets a poison counter.

{T}: Add {C}. {1}: Inkmoth Nexus becomes a 1/1 Phyrexian Blinkmoth artifact creature with flying and infect until end of turn. It's still a land. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Flying Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)

{B}: Vector Asp gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

If you control a commander, you may cast this spell without paying its mana cost. Exile target creature.

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

Change the target of target spell with a single target. You lose life equal to that spell's mana value.

Choose one — • Each opponent sacrifices a nontoken creature. • Each opponent sacrifices a creature token. • Each opponent sacrifices a planeswalker.

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

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

{T}: Add {B}. Cabal Pit deals 1 damage to you. Threshold — {B}, {T}, Sacrifice Cabal Pit: Target creature gets -2/-2 until end of turn. Activate only if seven or more cards are in your graveyard.

If Gemstone Caverns is in your opening hand and you're not the starting player, you may begin the game with Gemstone Caverns on the battlefield with a luck counter on it. If you do, exile a card from your hand. {T}: Add {C}. If Gemstone Caverns has a luck counter on it, instead add one mana of any color.

{T}: Add {C}. {4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

If Lake of the Dead would enter the battlefield, sacrifice a Swamp instead. If you do, put Lake of the Dead onto the battlefield. If you don't, put it into its owner's graveyard. {T}: Add {B}. {T}, Sacrifice a Swamp: Add {B}{B}{B}{B}.

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, 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.

{T}: Add {C}. {2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Peat Bog enters the battlefield tapped with two depletion counters on it. {T}, Remove a depletion counter from Peat Bog: Add {B}{B}. If there are no depletion counters on Peat Bog, sacrifice it.

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

({T}: Add {B}.)

{T}: Add {B}. Channel — {3}{B}, Discard Takenuma, Abandoned Mire: Mill three cards, then return a creature or planeswalker card from your graveyard to your hand. This ability costs {1} less to activate for each legendary creature you control.

Each land is a Swamp in addition to its other land types.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I — Urza's Saga gains "{T}: Add {C}." II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'" III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

{T}, Pay 1 life, Sacrifice Verdant Catacombs: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

+4: Target player exiles a card from their hand. −3: Exile target permanent. −14: Restart the game, leaving in exile all non-Aura permanent cards exiled with Karn Liberated. Then put those cards onto the battlefield under your control.

+1: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle. −3: Target creature gets +X/+X or -X/-X until end of turn, where X is the number of Swamps you control. −6: You get an emblem with "Swamps you control have '{T}: Add {B}{B}{B}{B}.'"

Whenever a creature you control dies, draw a card. +1: Create a 2/2 black Zombie creature token. −4: Each player sacrifices two creatures. −9: Each opponent chooses a permanent they control of each permanent type and sacrifices the rest.

Astral Cornucopia enters the battlefield with X charge counters on it. {T}: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.) Everflowing Chalice enters the battlefield with a charge counter on it for each time it was kicked. {T}: Add {C} for each charge counter on Everflowing Chalice.

Glistening Sphere enters the battlefield tapped. When Glistening Sphere enters the battlefield, proliferate. {T}: Add one mana of any color. Corrupted — {T}: Add three mana of any one color. Activate only if an opponent has three or more poison counters.

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

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

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Bottomless Vault enters the battlefield tapped. You may choose not to untap Bottomless Vault during your untap step. At the beginning of your upkeep, if Bottomless Vault is tapped, put a storage counter on it. {T}, Remove any number of storage counters from Bottomless Vault: Add {B} for each storage counter removed this way.

Charcoal Diamond enters the battlefield tapped. {T}: Add {B}.

Imprint — When Chrome Mox enters the battlefield, you may exile a nonartifact, nonland card from your hand. {T}: Add one mana of any of the exiled card's colors.

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

Enchant creature Enchanted creature has infect. At the beginning of your upkeep, put a -1/-1 counter on enchanted creature. When Glistening Oil is put into a graveyard from the battlefield, return Glistening Oil to its owner's hand.

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

Subterranean Hangar enters the battlefield tapped. {T}: Put a storage counter on Subterranean Hangar. {T}, Remove any number of storage counters from Subterranean Hangar: Add {B} for each storage counter removed this way.

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)