Soul Warden

Whenever another creature enters, you gain 1 life.

Spelltithe Enforcer

Whenever an opponent casts a spell, that player sacrifices a permanent unless they pay {1}.

Disruptive Pitmage

{T}: Counter target spell unless its controller pays {1}.
Morph {U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Court of Grace

When Court of Grace enters, you become the monarch.
At the beginning of your upkeep, create a 1/1 white Spirit creature token with flying. If you're the monarch, create a 4/4 white Angel creature token with flying instead.

Kataki, War's Wage

All artifacts have "At the beginning of your upkeep, sacrifice this artifact unless you pay {1}."

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Norn's Annex

({W/P} can be paid with either {W} or 2 life.)
Creatures can't attack you or planeswalkers you control unless their controller pays {W/P} for each of those creatures.

Mundungu

{T}: Counter target spell unless its controller pays {1} and 1 life.

Lim-Dûl's Hex

At the beginning of your upkeep, for each player, Lim-Dûl's Hex deals 1 damage to that player unless they pay {B} or {3}.

Zur the Enchanter

Flying
Whenever Zur the Enchanter attacks, you may search your library for an enchantment card with mana value 3 or less, put it onto the battlefield, then shuffle.

Archangel of Tithes

Flying
As long as Archangel of Tithes is untapped, creatures can't attack you or planeswalkers you control unless their controller pays {1} for each of those creatures.
As long as Archangel of Tithes is attacking, creatures can't block unless their controller pays {1} for each of those creatures.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Rhystic Circle

{1}: Any player may pay {1}. If no one does, the next time a source of your choice would deal damage to you this turn, prevent that damage.

Aether Barrier

Whenever a player casts a creature spell, that player sacrifices a permanent unless they pay {1}.

Broken Ambitions

Counter target spell unless its controller pays {X}. Clash with an opponent. If you win, that spell's controller mills four cards. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Soul Barrier

Whenever an opponent casts a creature spell, Soul Barrier deals 2 damage to that player unless they pay {2}.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Bloodchief Ascension

At the beginning of each end step, if an opponent lost 2 or more life this turn, you may put a quest counter on Bloodchief Ascension. (Damage causes loss of life.)
Whenever a card is put into an opponent's graveyard from anywhere, if Bloodchief Ascension has three or more quest counters on it, you may have that player lose 2 life. If you do, you gain 2 life.

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Strict Proctor

Flying
Whenever a permanent entering causes a triggered ability to trigger, counter that ability unless its controller pays {2}.

Mana Tithe

Counter target spell unless its controller pays {1}.

Unifying Theory

Whenever a player casts a spell, that player may pay {2}. If the player does, they draw a card.

Disruptive Student

{T}: Counter target spell unless its controller pays {1}.

Baird, Steward of Argive

Vigilance
Creatures can't attack you or planeswalkers you control unless their controller pays {1} for each of those creatures.

Dash Hopes

When you cast this spell, any player may pay 5 life. If a player does, counter Dash Hopes.
Counter target spell.

Shared Trauma

Join forces — Starting with you, each player may pay any amount of mana. Each player mills X cards, where X is the total amount of mana paid this way.

Ghostly Prison

Karmic Justice

Whenever a spell or ability an opponent controls destroys a noncreature permanent you control, you may destroy target permanent that opponent controls.

Archangel of Thune

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Whenever you gain life, put a +1/+1 counter on each creature you control.

Sunken Field

Enchant land
Enchanted land has "{T}: Counter target spell unless its controller pays {1}."

Windborn Muse

Flying
Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Pendrell Mists

All creatures have "At the beginning of your upkeep, sacrifice this creature unless you pay {1}."

Sphere of Safety

Creatures can't attack you or planeswalkers you control unless their controller pays {X} for each of those creatures, where X is the number of enchantments you control.

Explore the Vastlands

Each player looks at the top five cards of their library and may reveal a land card and/or an instant or sorcery card from among them. Each player puts the cards they revealed this way into their hand and the rest on the bottom of their library in a random order. Each player gains 3 life.

Wandering Archaic

Whenever an opponent casts an instant or sorcery spell, they may pay {2}. If they don't, you may copy that spell. You may choose new targets for the copy.

Wandering Archaic // Explore the Vastlands

Chancellor of the Annex

You may reveal this card from your opening hand. If you do, when each opponent casts their first spell of the game, counter that spell unless that player pays {1}.
Flying
Whenever an opponent casts a spell, counter it unless that player pays {1}.

Mesa Enchantress

Whenever you cast an enchantment spell, you may draw a card.

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Magus of the Tabernacle

Rhystic Cave

{T}: Choose a color. Add one mana of that color unless any player pays {1}. Activate only as an instant.

Mana Leak

Counter target spell unless its controller pays {3}.

Leonin Arbiter

Players can't search libraries. Any player may pay {2} for that player to ignore this effect until end of turn.

Cleric Class

(Gain the next level as a sorcery to add its ability.)
If you would gain life, you gain that much life plus 1 instead.
{3}{W}: Level 2
Whenever you gain life, put a +1/+1 counter on target creature you control.
{4}{W}: Level 3
When this Class becomes level 3, return target creature card from your graveyard to the battlefield. You gain life equal to that creature's toughness.

Samite Sanctuary

{2}: Prevent the next 1 damage that would be dealt to target creature this turn. Any player may activate this ability.

Zur's Weirding

Players play with their hands revealed.
If a player would draw a card, they reveal it instead. Then any other player may pay 2 life. If a player does, put that card into its owner's graveyard. Otherwise, that player draws a card.

Umbilicus

At the beginning of each player's upkeep, that player may pay 2 life. If they don't, they return a permanent they control to its owner's hand.

Blind Obedience

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Artifacts and creatures your opponents control enter tapped.

Killing Wave

For each creature, its controller sacrifices it unless they pay X life.

Rhystic Tutor

Unless any player pays {2}, search your library for a card, put that card into your hand, then shuffle.

Judge's Familiar

Flying
Sacrifice Judge's Familiar: Counter target instant or sorcery spell unless its controller pays {1}.

Righteous Valkyrie

Flying
Whenever another Angel or Cleric you control enters, you gain life equal to that creature's toughness.
As long as you have at least 7 life more than your starting life total, creatures you control get +2/+2.

Oloro, Ageless Ascetic

At the beginning of your upkeep, you gain 2 life.
Whenever you gain life, you may pay {1}. If you do, draw a card and each opponent loses 1 life.
At the beginning of your upkeep, if Oloro, Ageless Ascetic is in the command zone, you gain 2 life.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Painful Quandary

Whenever an opponent casts a spell, that player loses 5 life unless they discard a card.

Shrouded Serpent

Whenever Shrouded Serpent attacks, defending player may pay {4}. If that player doesn't, Shrouded Serpent can't be blocked this turn.