Lulu, Stern Guardian

Whenever an opponent attacks you, choose target creature attacking you. Put a stun counter on that creature.
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Dovin's Veto

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

Scroll of Isildur

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Gain control of up to one target artifact for as long as you control this Saga. The Ring tempts you.
II — Tap up to two target creatures. Put a stun counter on each of them.
III — Draw a card for each tapped creature target opponent controls.

Floodpits Drowner

Flash
Vigilance
When this creature enters, tap target creature an opponent controls and put a stun counter on it.
{1}{U}, {T}: Shuffle this creature and target creature with a stun counter on it into their owners' libraries.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Secret Identity

Choose one —
• Conceal — Until end of turn, target creature you control becomes a Citizen with base power and toughness 1/1 and gains hexproof.
• Reveal — Until end of turn, target creature you control becomes a Hero with base power and toughness 3/4 and gains flying and vigilance.

Alchemax Slayer-Bots

When this creature enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Azorius Signet

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.

Lyla, Holographic Assistant

Whenever you draw a card, put a +1/+1 counter on target creature.

Fellwar Stone

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

Summon: Valefor

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I — Sonic Wings — Each opponent chooses a creature with the greatest mana value among creatures they control. Return those creatures to their owners' hands.
II, III, IV — Tap up to one target creature and put a stun counter on it.
Flying

Karn's Bastion

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

Negate

Rhoda, Geist Avenger

Partner with Timin, Youthful Geist (When this creature enters, target player may put Timin into their hand from their library, then shuffle.)
Vigilance
Whenever a creature an opponent controls becomes tapped, if it isn't being declared as an attacker, put a +1/+1 counter on Rhoda.

Authority of the Consuls

Creatures your opponents control enter tapped.
Whenever a creature an opponent controls enters, you gain 1 life.

Sol Ring

Talisman of Progress

{T}: Add {C}.
{T}: Add {W} or {U}. This artifact deals 1 damage to you.

Ultros, Obnoxious Octopus

Whenever you cast a noncreature spell, if at least four mana was spent to cast it, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you cast a noncreature spell, if at least eight mana was spent to cast it, put eight +1/+1 counters on Ultros.

Solitary Sanctuary

When this enchantment enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you tap an untapped creature an opponent controls, put a +1/+1 counter on target creature you control.

Sharae of Numbing Depths

When Sharae enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you tap one or more untapped creatures your opponents control, draw a card. This ability triggers only once each turn.

Hylda of the Icy Crown

Whenever you tap an untapped creature an opponent controls, you may pay {1}. When you do, choose one —
• Create a 4/4 white and blue Elemental creature token.
• Put a +1/+1 counter on each creature you control.
• Scry 2, then draw a card.

Zygon Infiltrator

Body-print — {2}{U}: Tap another target creature and put a stun counter on it. This creature becomes a copy of that creature for as long as that creature remains tapped. Activate only as a sorcery. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Sanctuary Wall

Defender
{2}{W}, {T}: Tap target creature. You may put a stun counter on it. If you do, put a stun counter on this creature. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Tamiyo, the Moon Sage

+1: Tap target permanent. It doesn't untap during its controller's next untap step.
−2: Draw a card for each tapped creature target player controls.
−8: You get an emblem with "You have no maximum hand size" and "Whenever a card is put into your graveyard from anywhere, you may return it to your hand."

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on this creature.
When this creature dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on this creature. (They can't be blocked as long as defending player controls an Island.)

Everflowing Chalice

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

Grappling Kraken

Landfall — Whenever a land you control enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Dig Through Time

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Look at the top seven cards of your library. Put two of them into your hand and the rest on the bottom of your library in any order.

Patrolling Peacemaker

This creature enters with two +1/+1 counters on it.
Whenever an opponent commits a crime, proliferate. (They commit a crime if they target an opponent, anything an opponent controls, and/or cards in an opponent's graveyard. To proliferate, you choose any number of permanents and/or players, then give each another counter of each kind already there.)

Deepglow Skate

When this creature enters, double the number of each kind of counter on any number of target permanents.

Lost in the Maze

Flash
When this enchantment enters, tap X target creatures. Put a stun counter on each of those creatures you don't control. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Tapped creatures you control have hexproof.

Thought Vessel

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

Counterspell

Kitnap

Gift a card (You may promise an opponent a gift as you cast this spell. If you do, when it enters, they draw a card.)
Enchant creature
When this Aura enters, tap enchanted creature. If the gift wasn't promised, put three stun counters on it.
You control enchanted creature.

Staff of Compleation

{T}, Pay 1 life: Destroy target permanent you own.
{T}, Pay 2 life: Add one mana of any color.
{T}, Pay 3 life: Proliferate.
{T}, Pay 4 life: Draw a card.
{5}: Untap this artifact.

Mjölnir, Storm Hammer

When Mjölnir enters, attach it to target legendary creature you control.
Whenever equipped creature attacks, tap target creature defending player controls and put a stun counter on it. Then Mjölnir deals damage to each opponent equal to the number of tapped creatures that opponent controls.
Equip {4}

Verity Circle

Whenever a creature an opponent controls becomes tapped, if it isn't being declared as an attacker, you may draw a card.
{4}{U}: Tap target creature without flying.

Ripples of Potential

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

Timin, Youthful Geist

Partner with Rhoda, Geist Avenger (When this creature enters, target player may put Rhoda into their hand from their library, then shuffle.)
Flying
At the beginning of each combat, tap up to one target creature.

Sensational Spider-Man

Whenever Sensational Spider-Man attacks, tap target creature defending player controls and put a stun counter on it. Then you may remove up to three stun counters from among all permanents. Draw cards equal to the number of stun counters removed this way.

Cloud's Limit Break

Tiered (Choose one additional cost.)
• Cross-Slash — {0} — Destroy target tapped creature.
• Blade Beam — {1} — Destroy any number of target tapped creatures with different controllers.
• Omnislash — {3}{W} — Destroy all tapped creatures.

Flux Channeler

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

Gilded Scuttler

This creature can't be blocked.
When this creature enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

The Watcher in the Water

The Watcher in the Water enters tapped with nine stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you draw a card during an opponent's turn, create a 1/1 blue Tentacle creature token.
Whenever a Tentacle you control dies, untap up to one target Kraken and put a stun counter on up to one target nonland permanent.

Shackle Slinger

Whenever you cast your second spell each turn, choose target creature an opponent controls. If it's tapped, put a stun counter on it. Otherwise, tap it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Split Up

Choose one —
• Destroy all tapped creatures.
• Destroy all untapped creatures.

Summon: Shiva

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Heavenly Strike — Tap target creature an opponent controls. Put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
III — Diamond Dust — Draw a card for each tapped creature your opponents control.

Proft's Eidetic Memory

When Proft's Eidetic Memory enters, draw a card.
You have no maximum hand size.
At the beginning of combat on your turn, if you've drawn more than one card this turn, put X +1/+1 counters on target creature you control, where X is the number of cards you've drawn this turn minus one.

Ambling Stormshell

Ward {2}
Whenever this creature attacks, put three stun counters on it and draw three cards. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you cast a Turtle spell, untap this creature.

Nesting Grounds

{T}: Add {C}.
{1}, {T}: Move a counter from target permanent you control onto another target permanent. Activate only as a sorcery.

Fear of Sleep Paralysis

Flying
Eerie — Whenever this creature or another enchantment you control enters and whenever you fully unlock a Room, tap up to one target creature and put a stun counter on it.
Stun counters can't be removed from permanents your opponents control. (They won't untap if they have stun counters.)

Hylda's Crown of Winter

{1}, {T}: Tap target creature. This ability costs {1} less to activate during your turn.
{3}, Sacrifice Hylda's Crown of Winter: Draw a card for each tapped creature your opponents control.

Sleep

Tap all creatures target player controls. Those creatures don't untap during that player's next untap step.

Arcane Signet

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

Referee Squad

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Vigilance
When this creature enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Hide on the Ceiling

Exile X target artifacts and/or creatures. Return the exiled cards to the battlefield under their owners' control at the beginning of the next end step.

Mesmerizing Dose

Enchant creature
When this Aura enters, tap enchanted creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Enchanted creature doesn't untap during its controller's untap step.

Dreamtide Whale

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a player casts their second spell each turn, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)