Gonti, Night Minister

Whenever a player casts a spell they don't own, that player creates a Treasure token.
Whenever a creature deals combat damage to one of your opponents, its controller looks at the top card of that opponent's library and exiles it face down. They may play that card for as long as it remains exiled. Mana of any type can be spent to cast a spell this way.

Stolen Goods

Target opponent exiles cards from the top of their library until they exile a nonland card. Until end of turn, you may cast that card without paying its mana cost.

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Villainous Wealth

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.

Trygon Predator

Flying
Whenever this creature deals combat damage to a player, you may destroy target artifact or enchantment that player controls.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Sunken Hollow

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

Ukkima, Stalking Shadow

Partner with Cazur, Ruthless Stalker (When this creature enters, target player may put Cazur into their hand from their library, then shuffle.)
Ukkima can't be blocked.
When Ukkima leaves the battlefield, it deals X damage to target player and you gain X life, where X is its power.

Doc Aurlock, Grizzled Genius

Spells you cast from your graveyard or from exile cost {2} less to cast.
Plotting cards from your hand costs {2} less.

Tower Winder

Reach, deathtouch
When this creature enters, search your library and/or graveyard for a card named Command Tower, reveal it, and put it into your hand. If you search your library this way, shuffle.

Drowned Catacomb

This land enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Mind's Dilation

Whenever an opponent casts their first spell each turn, that player exiles the top card of their library. If it's a nonland card, you may cast it without paying its mana cost.

Plasm Capture

Counter target spell. At the beginning of your next first main phase, add X mana in any combination of colors, where X is that spell's mana value.

Gonti, Lord of Luxury

Deathtouch
When Gonti 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.

Felix Five-Boots

Menace, ward {2}
If a creature you control dealing combat damage to a player causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Flooded Grove

{T}: Add {C}.
{G/U}, {T}: Add {G}{G}, {G}{U}, or {U}{U}.

Island

Cunning Rhetoric

Whenever an opponent attacks you and/or one or more planeswalkers you control, exile the top card of that player's library. You may play that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast it.

Heartless Conscription

Exile all creatures. For each card exiled this way, you may play that card for as long as it remains exiled, and mana of any type can be spent to cast that spell. Exile Heartless Conscription.

Nashi, Moon Sage's Scion

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Nashi deals combat damage to a player, exile the top card of each player's library. Until end of turn, you may play one of those cards. If you cast a spell this way, pay life equal to its mana value rather than paying its mana cost.

Rampant Growth

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

Woodland Cemetery

This land enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Rogue's Passage

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

Orochi Soul-Reaver

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever one or more creatures you control deal combat damage to a player, create a Treasure token and manifest the top card of that player's library. (Put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Thieving Varmint

Deathtouch, lifelink
{T}, Pay 1 life: Add two mana of any one color. Spend this mana only to cast spells you don't own.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Changeling Outcast

Changeling (This card is every creature type.)
This creature can't block and can't be blocked.

Dazzling Sphinx

Flying
Whenever this creature deals combat damage to a player, that player exiles cards from the top of their library until they exile an instant or sorcery card. You may cast that card without paying its mana cost. Then that player puts the exiled cards that weren't cast this way on the bottom of their library in a random order.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Gonti, Canny Acquisitor

Spells you cast but don't own cost {1} less to cast.
Whenever one or more creatures you control deal combat damage to a player, look at the top card of that player's library, then exile it face down. You may play that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Cold-Eyed Selkie

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever this creature deals combat damage to a player, you may draw that many cards.

Fallen Shinobi

Ninjutsu {2}{U}{B} ({2}{U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, that player exiles the top two cards of their library. Until end of turn, you may play those cards without paying their mana costs.

Tinybones, Bauble Burglar

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.

Silent-Blade Oni

Ninjutsu {4}{U}{B} ({4}{U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, look at that player's hand. You may cast a spell from among those cards without paying its mana cost.

Arcane Heist

You may cast target instant or sorcery card from an opponent's graveyard without paying its mana cost. If that spell would be put into their graveyard, exile it instead.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Baleful Mastery

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.

Bribery

Search target opponent's library for a creature card and put that card onto the battlefield under your control. Then that player shuffles.

Arcane Signet

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

Smirking Spelljacker

Flash
Flying
When this creature enters, exile target spell an opponent controls.
Whenever this creature attacks, if a card is exiled with it, you may cast the exiled card without paying its mana cost.

Baleful Strix

Flying, deathtouch
When this creature enters, draw a card.

Ghostly Pilferer

Whenever this creature becomes untapped, you may pay {2}. If you do, draw a card.
Whenever an opponent casts a spell from anywhere other than their hand, draw a card.
Discard a card: This creature can't be blocked this turn.

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Edric, Spymaster of Trest

Whenever a creature deals combat damage to one of your opponents, its controller may draw a card.

Thief of Sanity

Flying
Whenever this creature deals combat damage to a player, look at the top three cards of that player's library, exile one of them face down, then put the rest into their graveyard. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Tasha, the Witch Queen

Whenever you cast a spell you don't own, create a 3/3 black Demon creature token.
+1: Draw a card. For each opponent, exile up to one target instant or sorcery card from that player's graveyard and put a page counter on it.
−3: You may cast a spell from among cards in exile with page counters on them without paying its mana cost.
Tasha, the Witch Queen can be your commander.

Shadowmage Infiltrator

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Whenever this creature deals combat damage to a player, you may draw a card.

Fellwar Stone

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

Outrageous Robbery

Target opponent exiles the top X cards of their library face down. You may look at and play those cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any type to cast it.

Dreamroot Cascade

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

Exotic Orchard

Slither Blade

Feed the Swarm

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

Court of Locthwain

When this enchantment enters, you become the monarch.
At the beginning of your upkeep, exile the top card of target opponent's library. You may play that card for as long as it remains exiled, and mana of any type can be spent to cast it. If you're the monarch, until end of turn, you may cast a spell from among cards exiled with this enchantment without paying its mana cost.

Rogue Class

(Gain the next level as a sorcery to add its ability.)
Whenever a creature you control deals combat damage to a player, exile the top card of that player's library face down. You may look at it for as long as it remains exiled.
{1}{U}{B}: Level 2
Creatures you control have menace.
{2}{U}{B}: Level 3
You may play cards exiled with this Class, and you may spend mana as though it were mana of any color to cast those spells.

Brainstealer Dragon

Flying
At the beginning of your end step, exile the top card of each opponent's library. You may play those cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.
Whenever a nonland permanent an opponent owns enters the battlefield under your control, they lose life equal to its mana value.

Twilight Mire

{T}: Add {C}.
{B/G}, {T}: Add {B}{B}, {B}{G}, or {G}{G}.

Sol Ring

Ohran Frostfang

Attacking creatures you control have deathtouch.
Whenever a creature you control deals combat damage to a player, draw a card.

Savvy Trader

When this creature enters, exile target permanent card from your graveyard. You may play that card for as long as it remains exiled.
Spells you cast from anywhere other than your hand cost {1} less to cast.

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Siphon Insight

Look at the top two cards of target opponent's library. Exile one of them face down and put the other on the bottom of that library. You may play the exiled card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell.
Flashback {1}{U}{B}

Gríma, Saruman's Footman

Gríma can't be blocked.
Whenever Gríma deals combat damage to a player, that player exiles cards from the top of their library until they exile an instant or sorcery card. You may cast that card without paying its mana cost. Then that player puts the exiled cards that weren't cast this way on the bottom of their library in a random order.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Hostage Taker

When this creature enters, exile another target creature or artifact until this creature leaves the battlefield. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Swamp

Thieving Skydiver

Kicker {X}. X can't be 0. (You may pay an additional {X} as you cast this spell.)
Flying
When this creature enters, if it was kicked, gain control of target artifact with mana value X or less. If that artifact is an Equipment, attach it to this creature.

Hinterland Harbor

This land enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Dream-Thief's Bandana

Whenever equipped creature deals combat damage to a player, look at the top card of their library, then exile it face down. For as long as it remains exiled, you may play it, and mana of any type can be spent to cast that spell.
Equip {1}

Shipwreck Marsh

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

Predators' Hour

Until end of turn, creatures you control gain menace and "Whenever this creature deals combat damage to a player, exile the top card of that player's library face down. You may look at and play that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell."

Triton Shorestalker

Command Tower

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Access Tunnel

{T}: Add {C}.
{3}, {T}: Target creature with power 3 or less can't be blocked this turn.

Forest

Culling Ritual

Destroy each nonland permanent with mana value 2 or less. Add {B} or {G} for each permanent destroyed this way.

Opulent Palace

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

Staff of Eden, Vault's Key

When Staff of Eden enters, put target legendary permanent card not named Staff of Eden, Vault's Key from a graveyard onto the battlefield under your control.
{T}: Draw a card for each permanent you control but don't own.