msem-instigator

Whenever Journeying Giftbearer or another nontoken creature you control enters, create a green and white Aura enchantment token named Wild Boon attached to that creature. The token has enchant creature and “Enchanted creature gets +1/+1.”

When Joyful Deviant enters or dies, it deals 1 damage to any target.

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.

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.)

When Judge of Clans enters, adjudicate. (Create a white enchantment Aura token with enchant creature and “Sacrifice this token: Untap enchanted creature.” attached to target creature.)
{T}: Add one mana of any color.

{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.

Juvenile Boa gets +2/+0 as long as you control a legendary creature.

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

Flash
Flying

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.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
Whenever an instant or sorcery card you own is exiled from anywhere, you gain 1 life.

Creature spells you cast with power 4 or greater cost {1} less to cast.

When Kalak Culler enters, each opponent loses life equal to the number of creatures you've sacrificed this turn.
Revive—{3}{B}, Sacrifice a creature. ({3}{B}, Sacrifice a creature, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Flying
Once during each of your turns, whenever you cast a spell from your graveyard, you may draw a card and create a tapped Treasure token.

Whenever Kalro Gritbrawler attacks, if you control a Desert or there is a Desert card in your graveyard, it gains double strike until end of turn.
Desertcycling {2} ({2}, Discard this card: Search your library for a Desert card, reveal it, and put it into your hand, then shuffle.)

Flying, haste
Ward—Pay 3 life.
The first Dragon spell you cast each turn costs {R}{R} less to cast. (This can reduce the amount of generic mana you pay.)

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 Kan'Gi, the Reverent perseveres, gain control of target creature an opponent controls with power less than or equal to Kan'Gi's power. (A creature perseveres when it survives damage.)

Rhapsody {5}{W}{W} (Pay {5}{W}{W} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
When Kan's Faithful enters, exile up to one target nonland permanent with mana value X or less until Kan's Faithful leaves the battlefield, where X is Kan's Faithful's power.

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

When Kaneh Scribe enters, amass Soldiers 2. (Put two +1/+1 counters on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)

Deathtouch

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.

Whenever a player discards a card, put a +1/+1 counter on Karatuy.
When a player has no cards in hand, Karatuy becomes a Demon and gains flying and lifelink. This ability triggers only once.
Demoncycling {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a Demon card, reveal it, put it into your hand, then shuffle.)