msem-instigator

Sacrifice two lands, Mill five cards: Return Jack, Horrific Harvester from your graveyard to your hand.
[+1]: You gain 2 life and each opponent loses 2 life.
[–2]: Return up to one target creature card and up to one target land card from your graveyard to your hand.
[–2]: Each opponent sacrifices the nonland permanent they control with the greatest mana value among permanents they control.

Vigilance
Augmented — Whenever Jacque attacks, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, you may exile any number of target nonland permanents, then return them to the battlefield tapped under their owners' control.

When Jahan, the Third Shah enters, shuffle your hand and graveyard into your library, then draw three cards.
Monument {3}{U}{U} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Whenever Jak, Daring Vanguard or another legendary creature you control enters, creatures you control get +1/+0 and gain haste until end of turn.

Flying, trample
At the beginning of combat on your turn, goad all creatures with power 3 or less. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)
Whenever a creature deals combat damage to an opponent, put a +1/+1 counter on it.

Activated abilities you activate cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.
Attain {5}{U} ({5}{U}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Trample
Whenever a creature card is put into your graveyard from anywhere, put a +1/+1 counter on Jawbone, Ravenous Mutant.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
{T}: The next creature spell you cast this turn has enspirit. When that creature enters, it becomes an enchantment in addition to its other types.

Once each turn, when Jeffery enters or you create an Aura token, you may create an Aura Role enchantment token named Lead Role attached to target creature you control. It's all colors and has enchant creature you control and “Enchanted creature has base power and toughness 5/5, is all creature types, and has flying, vigilance, trample, lifelink, and prowess.”
Whenever an enchanted creature you control attacks, draw a card.

Bloodprice {B}{B}{B}{B} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Lifelink, haste
Sacrifice another Demon: Jejun, Dark Hunter gains flying and indestructible until end of turn.

Flying
Once during each of your turns, for each creature you control, you may activate one of that creature's activated abilities with {T} in its cost without paying {T} and as though that creature had haste.

Whenever a creature you control enters, put a loyalty counter on Jenn, the Rising Dawn.
[0]: Target creature you control gets +1/+1 and gains first strike and lifelink until end of turn.
[–5]: Exile target creature.

Lifelink
Whenever Jerrold, Fugitive or another creature you control enters, if you cast it, you may cast target instant or sorcery card from your graveyard with lesser mana value by paying life equal to its mana value rather than paying its mana cost. Exile that card instead of putting it anywhere else as it resolves.

Creatures you control have “Whenever this creature attacks, put a +1/+1 counter on target creature with lesser power.”
At the beginning of each end step, if there are five or more +1/+1 counters among creatures you control, destroy up to one target artifact or enchantment.

[+2]: Up to one target creature gets +1/+0 and gains first strike and haste until end of turn.
[–3]: Jeska deals 3 damage to target creature. If that creature is an artifact, she deals 5 damage instead.
[–10]: You get an emblem with “Creatures you control get +2/+0.” and “All creatures have haste and can't block.”

Hexproof
At the beginning of each end step, if an opponent was dealt 4 or more damage this turn, return target instant or sorcery card from your graveyard to your hand.

Reach
Whenever another creature you control becomes the target of an instant or sorcery spell, that creature gets +3/+3 until end of turn.

Renown 1
Whenever a creature you control becomes renowned, exile the top card of your library. You may play that card this turn.

Players play with the top card of their libraries revealed.
At the beginning of your first main phase, add {G}{G} for each land card among cards on top of libraries.
Jindao, the Coiled Prophet gets +2/+2 for each creature card among cards on top of libraries.

You may look at the top card of your library any time.
Once during each of your turns, you may play a land from the top of your library as though you could play an additional land.
{3}{G}{G}: You may cast the top card of your library without paying its mana cost if it's a creature card. Activate only as a sorcery.

Other attacking Foxes you control get +1/+0.
{2}{R}, Sacrifice Jiu: Discard your hand, then draw a card for each tapped Fox you control.

Whenever one or more creatures deal combat damage to you, put a -1/-1 counter on one of them.
Attain {5}{W} ({5}{W}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

When Jobiah, Devoted Farmer enters, search your library for a land card, put it onto the battlefield tapped, then shuffle.
At the beginning of your upkeep, if you control six or more lands with different names, you may transform Jobiah.

Johanna, Skarvith Marshal has first strike as long as it's attacking.
Whenever you attack, you may pay {X}{R/W}{R/W}. When you do, put a +1/+1 counter on each of up to X target attacking creatures. Those creatures gain first strike until end of turn.

If another creature you control would die, exile it instead.
When John Furo, the Unfortunate dies, until your next end step, you may play cards exiled with John Furo.