msem-instigator

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{G}, Sacrifice Jade Vault Reclaimer: Destroy target artifact or enchantment.

Menace
Augmented — Whenever you cast a spell, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Jaded Guardian. It loses this ability and gains “Whenever this creature attacks, defending player sacrifices two permanents.”

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.)

Jara Favored gets +2/+2 as long as you've lost life this turn.

Trample, haste
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Menace
Inspired — Whenever Jeering Kit becomes untapped, target Fox you control gets +1/+1 until end of turn.

Haste
When Jetskate enters, if you've drawn two or more cards this turn, it deals 2 damage to any target.
Cycling {R} ({R}, Discard this card: Draw a card.)

Vigilance
{1}{W}: Jhessian Cavalier gains lifelink until end of turn.

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.)

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

Double strike, menace, trample
At the beginning of your end step, sacrifice Juddering Mishap unless you've cast a spell with no creature types this turn. (Noncreature spells have no creature types.)

Menace
Swampcycling {1}, forestcycling {1} ({1}, Discard this card: Search your libary for a Swamp or Forest card, reveal it, put it into your hand, then shuffle.)

{1}{R}: Exile the top card of your library. If it's a creature card, you may play it until the end of your next turn.
{4}{W}: Put two +1/+1 counters on target creature.

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.

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.

Whenever an artifact you control becomes tapped, K-17 Drone deals 1 damage to each opponent.

Haste
Whenever another creature you control dies, you may return an Aura that was attached to that creature to the battlefield attached to Kafyabari Enforcer.

When this creature enters, put two -1/-1 counters on a creature you control.
When this creature dies, put a -1/-1 counter on up to one target creature for each -1/-1 counter on this creature.

When Kahroba Patrol dies, you may search your library for a basic land or Satrapy card, reveal it, put it into your hand, then shuffle.

As long as it's your turn, Kamito Champion has first strike.
Kamito Champion gets +1/+1 as long as it's equipped, enchanted, or has a card inscribed onto it.

Kamito Pathseeker can't block.
{3}{R}, Exile Kamito Pathseeker from your graveyard: Return target instant or sorcery card from your graveyard to your hand.

{T}: Kanaan Wardriver deals 1 damage to target creature you control. That creature gains haste until end of turn.

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.)
When Kantra of Avarice enters, target player draws two cards and loses 2 life.

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.)
Trample