msem-instigator

Menace, lifelink
Whenever Jonah of the Spellbane deals combat damage to a player, destroy target creature or planeswalker, then scry 1.

Vigilance, haste
All creatures able to block Jormir, Who Encircles All do so.
Jormir, Who Encircles All can block any number of creatures.

Exile up to one target nonland permanent you control and up to one target nonland permanent card with mana value 3 or less from your graveyard. Then return the exiled cards to the battlefield tapped under their owner's control.

When Journey to Elrayin enters, journey, then choose a creature card name. (To journey, exile the top card of your library face up. Whenever a creature you control deals combat damage to a player, put a journeyed card you own into your hand.)
Whenever a creature you control with the chosen name deals combat damage to a player, journey.

Put target creature or planeswalker on the bottom of its owner's library. Its controller may scry 1.

As Joyous Chromatelk enters, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.
{T}: Add one mana of the chosen color.

Archive 3 (As this enters, shuffle the top three cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, you exile up to one target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

[+2]: Exile another target permanent, then return it to the battlefield under its owner's control.
[–2]: Gain control of target creature unless its controller pays its mana cost.
[–5]: You get an emblem with “If a nonland permanent would enter and it wasn't cast, it you control enters instead.”

Flash
Vanishing 3 (This permanent enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Judge's Decree enters, exile another target spell or nonland permanent. When Judge's Decree is no longer on the battlefield, the exiled card's owner may cast that card without paying its mana cost.

Noncreature spells your opponents cast cost {1} more to cast for each counter on Judges of Bearidge.
{5}{W}{U}: Put a +1/+1 counter on Judges of Bearidge, then detain each creature with lesser power. (Until your next turn, those permanents can't attack or block and their activated abilities can't be activated.)

Judgment of Hao'Tai deals 4 damage to each non-Dragon creature.

Judge target creature you control. If you honored it, it deals damage to each other creature equal to its power. If you condemned it, return up to two creature cards with lesser mana value than the sacrificed creature from your graveyard to the battlefield. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

When Jumbo Shrimp enters or when you cycle it, destroy target noncreature permanent.
Cycling {3}{G}{G} ({3}{G}{G}, Discard this card: Draw a card.)

Return target creature card from a graveyard to the battlefield. Then if that card wasn't put into a graveyard from the battlefield this turn, exile it.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{1}, {T}: Choose a nonland card name. Reveal the top three cards of your library and put each revealed card with that name into your hand. Put the rest into your graveyard.

At the beginning of each player's upkeep, that player may sacrifice a creature. If they don't, they discard a card.

Choose two —
• Jund Command deals 3 damage to each non-Dragon creature.
• Jund Command deals 4 damage to each opponent.
• Each opponent sacrifices a planeswalker.
• Mill five cards. Return a permanent card milled this way to your hand.

When Junktrawler enters, create a tapped colorless Powercell artifact token with “{T}: Add {C}.”
Tap another untapped artifact you control: Junktrawler gets +1/+1 until end of turn.

Target player sacrifices a legendary creature or planeswalker.

Flash
Flying
When Justiciar Overseer enters, the next 2 damage that a source of your choice would deal to you and/or permanents you control this turn is dealt to any target instead.

(Choose only one work as a sorcery to add its ability.)
When Juyu Offering Pool enters, reveal the top five cards of your library. You may put a noncreature card from among them into your hand. Put the rest on the bottom of your library in any order.
{1}{U}: Scales of Shara
Whenever you cast a noncreature spell, put a +1/+1 counter on target creature you control.
{6}{U}{U}: Eye of Shojiro
Whenever you cast a noncreature spell, create an 8/8 blue Kraken creature token.

First strike
Spells can't be cast except during their controller's turns.
Whenever a creature attacks you, Ka Soma deals 1 damage to that creature's controller unless that player pays {1}.

Flying
When Kaalia's Abomination enters or dies, it deals 2 damage to target opponent. Then that player discards two cards.

Flying, lifelink
Whenever Kaalia, Sky's End attacks, it deals 2 damage to any target. It deals an additional 2 damage to that target if you control an Angel. The same is true if you control a Demon. The same is true if you control a Dragon.

You don't lose the game for drawing from an empty library.
As long as you have seven or fewer cards in each of your libraries, you may cast spells without paying their mana costs.