msem-instigator

Menace (This creature can't be blocked except by two or more creatures.)
Itava Warshrieker attacks each combat if able.

Paranoia—Reappropriate white. (You may cast this spell by exiling two white cards from your hand and/or graveyard when a permanent you control leaves the battlefield.)
When Ivenge's Evangel enters, create a 1/1 white Cleric creature token and you gain 1 life.

If an enchanted permanent you control would leave the battlefield, instead destroy one of the Auras attached to it, then that permanent phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

{T}: Izahl, the Stormbringer deals 1 damage to any target.
Whenever you cast a noncreature spell, you may untap target creature you control.

When Jade Empire Cartographer enters, choose one —
• Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
• Put a +1/+1 counter on target creature you control.

{1}, {T}: Put a +1/+1 counter on Jade Sentinel. Activate only if you control a creature with power greater than Jade Sentinel's.

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.

As long as Jadycian Empath is on the battlefield or in your graveyard, it's a land in addition to its other types.
Sacrifice Jadycian Empath: Add one mana of any color.

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

Menace
Jara Champion can only attack or block alone.
Whenever one or more players lose life for the first time each turn, put a +1/+1 counter on Jara Champion.

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.)

When Jidai Clairvoyant enters, create a 2/2 colorless Spirit creature token.
Whenever a colorless creature you control enters, you may draw a card.

You may play lands from graveyards.
{9}{G}{G}: Put nine +1/+1 counters on Jirada, Elder of Caulte.

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 a land you control enters, create a 1/1 colorless Servo artifact creature token.
{4}{G}{W}: Put a +1/+1 counter on each creature you control. They gain trample until end of turn.

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.)

{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.

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.

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.

Whenever you cast a noncreature spell, you may pay {R}. If you do, untap Kamito Rageweaver.
{T}: Kamito Rageweaver deals 1 damage to target player.

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

Kanvar can't attack or block.
Whenever a creature you control with power 4 or greater dies, draw a card.
{R}{G}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words “when,” “whenever,” or “at.”)

When Kaone enters, if it was cast, exile target instant or sorcery card from your graveyard. If its mana value is less than or equal to the number of spells you've cast this turn, you may cast a copy of that spell without paying its mana cost. If you don't cast a copy this way, put the exiled card into your hand.