Fuel for the Cause

Counter target spell, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Spectral Searchlight

{T}: Choose a player. That player adds one mana of any color they choose.

Keskit, the Flesh Sculptor

{T}, Sacrifice three other artifacts and/or creatures: Look at the top three cards of your library. Put two of them into your hand and the other into your graveyard.
Partner (You can have two commanders if both have partner.)

Vivid Creek

Vivid Creek enters tapped with two charge counters on it.
{T}: Add {U}.
{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.

Empowered Autogenerator

Empowered Autogenerator enters tapped.
{T}: Put a charge counter on Empowered Autogenerator. Add X mana of any one color, where X is the number of charge counters on Empowered Autogenerator.

Parallax Wave

Fading 5 (This enchantment enters with five fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
Remove a fade counter from Parallax Wave: Exile target creature.
When Parallax Wave leaves the battlefield, each player returns to the battlefield all cards they own exiled with Parallax Wave.

Magistrate's Scepter

{4}, {T}: Put a charge counter on Magistrate's Scepter.
{T}, Remove three charge counters from Magistrate's Scepter: Take an extra turn after this one.

Midnight Oil

Midnight Oil enters with seven hour counters on it.
At the beginning of your draw step, draw an additional card and remove two hour counters from Midnight Oil.
Your maximum hand size is equal to the number of hour counters on Midnight Oil.
Whenever you discard a card, you lose 1 life.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Teysa, Envoy of Ghosts

Vigilance, protection from creatures
Whenever a creature deals combat damage to you, destroy that creature. Create a 1/1 white and black Spirit creature token with flying.

Winding Constrictor

If one or more counters would be put on an artifact or creature you control, that many plus one of each of those kinds of counters are put on that permanent instead.
If you would get one or more counters, you get that many plus one of each of those kinds of counters instead.

Mindbender Spores

Defender (This creature can't attack.)
Flying
Whenever Mindbender Spores blocks a creature, put four fungus counters on that creature. The creature gains "This creature doesn't untap during your untap step if it has a fungus counter on it" and "At the beginning of your upkeep, remove a fungus counter from this creature."

Vorel of the Hull Clade

{G}{U}, {T}: Double the number of each kind of counter on target artifact, creature, or land.

Grim Affliction

Put a -1/-1 counter on target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Ugin, the Spirit Dragon

+2: Ugin, the Spirit Dragon deals 3 damage to any target.
−X: Exile each permanent with mana value X or less that's one or more colors.
−10: You gain 7 life, draw seven cards, then put up to seven permanent cards from your hand onto the battlefield.

Grimoire of the Dead

{1}, {T}, Discard a card: Put a study counter on Grimoire of the Dead.
{T}, Remove three study counters from Grimoire of the Dead and sacrifice it: Put all creature cards from all graveyards onto the battlefield under your control. They're black Zombies in addition to their other colors and types.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Elesh Norn, Grand Cenobite

Vigilance
Other creatures you control get +2/+2.
Creatures your opponents control get -2/-2.

Fathom Mage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever a +1/+1 counter is put on Fathom Mage, you may draw a card.

Atraxa, Praetors' Voice

Flying, vigilance, deathtouch, lifelink
At the beginning of your end step, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Volrath, the Shapestealer

At the beginning of combat on your turn, put a -1/-1 counter on up to one target creature.
{1}: Until your next turn, Volrath, the Shapestealer becomes a copy of target creature with a counter on it, except it's 7/5 and it has this ability.

Simic Ascendancy

{1}{G}{U}: Put a +1/+1 counter on target creature you control.
Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on Simic Ascendancy.
At the beginning of your upkeep, if Simic Ascendancy has twenty or more growth counters on it, you win the game.

Steady Progress

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

Guul Draz Assassin

Level up {1}{B} ({1}{B}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 2-3
2/2
{B}, {T}: Target creature gets -2/-2 until end of turn.
LEVEL 4+
4/4
{B}, {T}: Target creature gets -4/-4 until end of turn.

Private Research

Enchant creature
At the beginning of your upkeep, you may put a page counter on Private Research.
When enchanted creature dies, draw a card for each page counter on Private Research.

Shrine of Piercing Vision

At the beginning of your upkeep and whenever you cast a blue spell, put a charge counter on Shrine of Piercing Vision.
{T}, Sacrifice Shrine of Piercing Vision: Look at the top X cards of your library, where X is the number of charge counters on Shrine of Piercing Vision. Put one of those cards into your hand and the rest on the bottom of your library in any order.

Twilight Mire

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

Crib Swap

Changeling (This card is every creature type.)
Exile target creature. Its controller creates a 1/1 colorless Shapeshifter creature token with changeling.

Expedition Map

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

Astral Cornucopia

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

Shimmer Dragon

Flying
As long as you control four or more artifacts, Shimmer Dragon has hexproof. (It can't be the target of spells or abilities your opponents control.)
Tap two untapped artifacts you control: Draw a card.

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Azor's Elocutors

At the beginning of your upkeep, put a filibuster counter on Azor's Elocutors. Then if Azor's Elocutors has five or more filibuster counters on it, you win the game.
Whenever a source deals damage to you, remove a filibuster counter from Azor's Elocutors.

Pyramid of the Pantheon

{2}, {T}: Add one mana of any color. Put a brick counter on Pyramid of the Pantheon.
{T}: Add three mana of any one color. Activate only if there are three or more brick counters on Pyramid of the Pantheon.

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Veteran Explorer

When Veteran Explorer dies, each player may search their library for up to two basic land cards, put them onto the battlefield, then shuffle.

Lux Cannon

{T}: Put a charge counter on Lux Cannon.
{T}, Remove three charge counters from Lux Cannon: Destroy target permanent.

Everflowing Chalice

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

Vedalken Infuser

At the beginning of your upkeep, you may put a charge counter on target artifact.

Gemstone Mine

Gemstone Mine enters with three mining counters on it.
{T}, Remove a mining counter from Gemstone Mine: Add one mana of any color. If there are no mining counters on Gemstone Mine, sacrifice it.

Jin-Gitaxias, Core Augur

Flash
At the beginning of your end step, draw seven cards.
Each opponent's maximum hand size is reduced by seven.

Legacy's Allure

At the beginning of your upkeep, you may put a treasure counter on Legacy's Allure.
Sacrifice Legacy's Allure: Gain control of target creature with power less than or equal to the number of treasure counters on Legacy's Allure. (This effect lasts indefinitely.)

Inspiring Statuary

Nonartifact spells you cast have improvise. (Your artifacts can help cast those spells. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Foundry Inspector

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

Endless Scream

Enchant creature
Endless Scream enters with X scream counters on it.
Enchanted creature gets +1/+0 for each scream counter on Endless Scream.

Remote Farm

Remote Farm enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from Remote Farm: Add {W}{W}. If there are no depletion counters on Remote Farm, sacrifice it.

Deepglow Skate

When Deepglow Skate enters, double the number of each kind of counter on any number of target permanents.

Sword of Truth and Justice

Equipped creature gets +2/+2 and has protection from white and from blue.
Whenever equipped creature deals combat damage to a player, put a +1/+1 counter on a creature you control, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Equip {2}

Glint-Sleeve Siphoner

Menace
Whenever Glint-Sleeve Siphoner enters or attacks, you get {E} (an energy counter).
At the beginning of your upkeep, you may pay {E}{E}. If you do, you draw a card and you lose 1 life.

Eternity Vessel

Eternity Vessel enters with X charge counters on it, where X is your life total.
Landfall — Whenever a land you control enters, you may have your life total become the number of charge counters on Eternity Vessel.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Essence Bottle

{3}, {T}: Put an elixir counter on Essence Bottle.
{T}, Remove all elixir counters from Essence Bottle: You gain 2 life for each elixir counter removed this way.

Conversion Chamber

{2}, {T}: Exile target artifact card from a graveyard. Put a charge counter on Conversion Chamber.
{2}, {T}, Remove a charge counter from Conversion Chamber: Create a 3/3 colorless Phyrexian Golem artifact creature token.

Iceberg

Iceberg enters with X ice counters on it.
{3}: Put an ice counter on Iceberg.
Remove an ice counter from Iceberg: Add {C}.

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Armillary Sphere

{2}, {T}, Sacrifice Armillary Sphere: Search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.

Life Matrix

{4}, {T}: Put a matrix counter on target creature and that creature gains "Remove a matrix counter from this creature: Regenerate this creature." Activate only during your upkeep.

Gilder Bairn

{2}{G/U}, {Q}: Double the number of each kind of counter on target permanent. ({Q} is the untap symbol.)

Call for Unity

Revolt — At the beginning of your end step, if a permanent you controlled left the battlefield this turn, put a unity counter on Call for Unity.
Creatures you control get +1/+1 for each unity counter on Call for Unity.

Archmage Ascension

At the beginning of each end step, if you drew two or more cards this turn, you may put a quest counter on Archmage Ascension.
As long as Archmage Ascension has six or more quest counters on it, if you would draw a card, you may instead search your library for a card, put that card into your hand, then shuffle.

Viral Drake

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Thopter Foundry

{1}, Sacrifice a nontoken artifact: Create a 1/1 blue Thopter artifact creature token with flying. You gain 1 life.

Sigil of Distinction

Sigil of Distinction enters with X charge counters on it.
Equipped creature gets +1/+1 for each charge counter on Sigil of Distinction.
Equip—Remove a charge counter from Sigil of Distinction.

As Foretold

At the beginning of your upkeep, put a time counter on As Foretold.
Once each turn, you may pay {0} rather than pay the mana cost for a spell you cast with mana value X or less, where X is the number of time counters on As Foretold.

Terramorphic Expanse

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

Merieke Ri Berit

Merieke Ri Berit doesn't untap during your untap step.
{T}: Gain control of target creature for as long as you control Merieke Ri Berit. When Merieke Ri Berit leaves the battlefield or becomes untapped, destroy that creature. It can't be regenerated.

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Mace of the Valiant

Equipped creature gets +1/+1 for each charge counter on Mace of the Valiant and has vigilance. (Attacking doesn't cause it to tap.)
Whenever a creature you control enters, put a charge counter on Mace of the Valiant.
Equip {3}

Contagion Engine

When Contagion Engine enters, put a -1/-1 counter on each creature target player controls.
{4}, {T}: Proliferate twice. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Commander's Sphere

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

Silence

Your opponents can't cast spells this turn.

Icatian Moneychanger

Icatian Moneychanger enters with three credit counters on it.
When Icatian Moneychanger enters, it deals 3 damage to you.
At the beginning of your upkeep, put a credit counter on Icatian Moneychanger.
Sacrifice Icatian Moneychanger: You gain 1 life for each credit counter on Icatian Moneychanger. Activate only during your upkeep.

Spread the Sickness

Destroy target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Dreadship Reef

{T}: Add {C}.
{1}, {T}: Put a storage counter on Dreadship Reef.
{1}, Remove X storage counters from Dreadship Reef: Add X mana in any combination of {U} and/or {B}.

Glacian, Powerstone Engineer

{T}, Tap X untapped artifacts you control: Look at the top X cards of your library. Put one of those cards into your hand and the rest into your graveyard.
Partner (You can have two commanders if both have partner.)