MTG Toxrill, the Corrosive Deck by Scarecrow21

At the beginning of each end step, put a slime counter on each creature you don't control. Creatures you don't control get -1/-1 for each slime counter on them. Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token. {U}{B}, Sacrifice a Slug: Draw a card.

Deathtouch Whenever Tinybones deals combat damage to a player, you may cast target nonland permanent card from that player's graveyard, and mana of any type can be spent to cast that spell.

Flying Whenever a player casts their second spell each turn, this creature connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Flash When this creature enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

At the beginning of your end step, if you control no creatures with decayed, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Whenever an opponent discards a card, exile it from their graveyard with a stash counter on it. During your turn, you may play cards you don't own with stash counters on them from exile, and mana of any type can be spent to cast those spells. {3}{B}, {T}: Each opponent discards a card. Activate only as a sorcery.

Flash Whenever a creature you control deals combat damage to a player, draw a card. When Enduring Curiosity dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

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

Trample Whenever a source deals damage to this creature, that source's controller sacrifices that many permanents of their choice.

Flash When Ertai Resurrected enters, choose up to one — • Counter target spell, activated ability, or triggered ability. Its controller draws a card. • Destroy another target creature or planeswalker. Its controller draws a card.

When Rusko, Clockmaker enters the battlefield, conjure a card named Midnight Clock onto the battlefield. Whenever you cast a noncreature spell, put an hour counter on each permanent you control named Midnight Clock. Each opponent loses 1 life and you gain 1 life.

Flying, trample Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.) At the beginning of your end step, you draw X cards and lose X life, where X is your speed.

Flash This spell can't be countered. Whenever you cast a spell, choose up to one — • Return target spell you don't control to its owner's hand. • Return target nonland permanent to its owner's hand.

{T}: Add one mana of any color among legendary creatures and planeswalkers you control.

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

{T}: Add {U}. {2}{U}: Put an hour counter on this artifact. At the beginning of each upkeep, put an hour counter on this artifact. When the twelfth hour counter is put on this artifact, shuffle your hand and graveyard into your library, then draw seven cards. Exile this artifact.

When Tinybones Joins Up enters, any number of target players each discard a card. Whenever a legendary creature you control enters, any number of target players each mill a card and lose 1 life.

At the beginning of your first main phase, choose one or more — • Sell Contraband — Create a Treasure token. You lose 1 life. • Buy Information — Draw a card. You lose 2 life. • Hire a Mercenary — Create a 3/2 colorless Shapeshifter creature token with changeling. You lose 3 life. (It is every creature type.)

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 — Target opponent reveals their hand. You choose a creature or planeswalker card from it. That player discards that card. II — Search your library for a card, put that card into your hand, then shuffle. You lose 3 life. III — Put target creature card from a graveyard onto the battlefield under your control.

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.) Draw a card.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.) Draw a card.

Spree (Choose one or more additional costs.) + {1}{U} — Counter target spell. + {3} — Create a token that's a copy of target artifact or creature you control. + {2} — Draw two cards, then discard a card.

Cleave {1}{U}{U} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.) Counter target spell [that wasn't cast from its owner's hand].

Add {B}{B}{B}.

Choose one — • Counter target spell with mana value 2 or less. • Counter target red or green spell with mana value 6 or less.

Draw a card. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Counter target spell.

Choose one — • Counter target creature or enchantment spell. • Return one or two target creatures and/or enchantments you own to your hand.

Gift a card (You may promise an opponent a gift as you cast this spell. If you do, they draw a card before its other effects.) Counter target creature spell. If the gift was promised, instead counter target spell.

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

As an additional cost to cast this spell, discard a card or pay 3 life. Destroy target creature or planeswalker.

As an additional cost to cast this spell, forage or pay {B}. (To forage, exile three cards from your graveyard or sacrifice a Food.) Destroy target creature or planeswalker.

Destroy target nonartifact creature.

Destroy target creature. You lose 2 life.

Destroy target non-Angel, non-Demon, non-Devil, non-Dragon creature.

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

Destroy target non-outlaw creature. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws. Everyone else is fair game.)

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Look at the top X cards of your library, where X is the amount of mana spent to cast this spell. Put two of them into your hand and the rest on the bottom of your library in a random order. Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

You may pay {1}{B} rather than pay this spell's mana cost. If the {1}{B} cost was paid, an opponent draws a card. Exile target creature or planeswalker.

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.) Draw a card.

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.

Destroy target creature.

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

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.) Search your library for a card, exile it face down, then shuffle. If this spell was bargained, you may cast the exiled card without paying its mana cost if that spell's mana value is 4 or less. Put the exiled card into your hand if it wasn't cast this way.

Target player takes an extra turn after this one.

You may pay {B} rather than pay this spell's mana cost if there are thirteen or more creatures on the battlefield. Each player sacrifices thirteen creatures of their choice.

As an additional cost to cast this spell, you may collect evidence 6. Destroy all creatures. If evidence was collected, exile a card from an opponent's graveyard. Then search its owner's graveyard, hand, and library for any number of cards with that name and exile them. That player shuffles, then draws a card for each card exiled from their hand this way.

Council's dilemma — Starting with you, each player votes for time or money. For each time vote, take an extra turn after this one. For each money vote, choose a permanent owned by the voter and gain control of it. Exile Expropriate.

Each opponent can't draw more than one card each turn. −2: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

+1: Each player discards a card. −2: Target player sacrifices a creature. −6: Separate all permanents target player controls into two piles. That player sacrifices all permanents in the pile of their choice.

At the beginning of your end step, if Kaito entered this turn, he phases out. +1: Draw a card. Then discard a card unless you attacked this turn. −2: Create a 1/1 blue Ninja creature token with "This token can't be blocked." −7: You get an emblem with "Whenever a creature you control deals combat damage to a player, search your library for a blue or black creature card, put it onto the battlefield, then shuffle."

+2: Look at the top card of target player's library. You may put that card on the bottom of that player's library. 0: Draw three cards, then put two cards from your hand on top of your library in any order. −1: Return target creature to its owner's hand. −12: Exile all cards from target player's library, then that player shuffles their hand into their library.

As long as The Aetherspark is attached to a creature, The Aetherspark can't be attacked and has "Whenever equipped creature deals combat damage during your turn, put that many loyalty counters on The Aetherspark." +1: Attach The Aetherspark to up to one target creature you control. Put a +1/+1 counter on that creature. −5: Draw two cards. −10: Add ten mana of any one color.

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

If you control two or more other lands, this land enters tapped. {T}: Add {U}. {5}{U}: Until end of turn, this land becomes a 7/7 blue Giant creature with ward {3}. It's still a land. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)

({T}: Add {U}.)

{T}: Add {U}. Channel — {3}{U}, Discard this card: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

({T}: Add {B}.)

{T}: Add {B}. Channel — {3}{B}, Discard this card: 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.

This land enters tapped unless you control two or fewer other lands. {T}: Add {U} or {B}.

This land enters tapped unless you control two or more other lands. {T}: Add {U} or {B}.

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 {U} or {B}.

As this land enters, choose a creature type. {T}: Add {C}. {T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

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

{T}: Add {C}. {2}, {T}, Sacrifice this land: Destroy target nonbasic land an opponent controls. That land's controller may search their library for a basic land card, put it onto the battlefield, then shuffle. You may search your library for a basic land card, put it onto the battlefield, then shuffle.

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

{T}: Add {C}. {2}, {T}, Sacrifice this land: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.