msem-instigator

Improve {R/W} ({R/W}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever an embattled creature you control attacks, you may exile the top card of your library. During any turn you attacked with an embattled creature, you may play that card. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, scry 1, then exile the top card of your library. Until end of turn, you may play that card.

Kinjiru Assailant has haste as long as an opponent controls a nonbasic land.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{B}{B}: Choose any number of other nontoken creatures you control. Whenever one of those creatures dies this turn, create a token that's a copy of that creature, except it has no mana cost.

When Kinken, the Dragon's Breath enters, draw a card, then choose a creature card name.
Whenever a creature you control with the chosen name attacks, you may pay {1}. If you do, create a token that's a copy of it and that's tapped and attacking, except it isn't legendary. Exile the token at the beginning of the end step.

Lifelink
Whenever a creature with power less than Kiri, Cloudwalker's power you control enters, you may pay {W}. If you do, you gain 2 life and draw a card.

Lifelink
Whenever one or more other creatures with power 2 or less you control enters, you gain 1 life. If your life total is greater than your starting life total, draw a card instead. This ability triggers only once each turn.

Whenever you cast a spell that targets one or more permanents you don't control, gain control of those permanents until end of turn. Untap them. They gain haste until end of turn.

Whenever one or more other creatures you control enter, upgrade each creature you control. (Give each one of the listed counters it doesn't already have. Upgrades are independent.)
• +1/+1
• Flying
• First strike
• Vigilance
• Lifelink

Prowess
Whenever Knight-Academic attacks, scry 1.

This spell costs {1} less to cast for each embattled creature you control. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)
Haste
Whenever Knights of the Burning Pyre attacks, it deals X damage to each opponent, where X is the number of embattled creatures you control.

Whenever Knotweald Ambassador becomes the target of a spell or ability an opponent controls, choose one —
• Knotweald Ambassador deals damage equal to its power to target creature or planeswalker that player controls.
• Draw a card.

At the beginning of your end step, if an opponent lost life this turn, Kogane the Crimson Consort deals 2 damage to each opponent and you gain 2 life.

First strike
Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
{6}, {T}: Search your library for a creature card with distorted, put it onto the battlefield, then shuffle.

Trample
Whenever Komurk Harvester or another creature you control dies, draw cards equal to that creature's power.

Flying
Whenever you cast a spell, exile the top card of your library.
At the beginning of your end step, put a card exiled with Korephyr, Riddle Sage into its owner's hand. Put each other card exiled with Korephyr on the bottom of its owner's library in a random order.
{3}{U/B}: Scry 2.

Kicker {X} (You may pay an additional {X} as you cast this spell.)
When Korrinary Warcaller enters, if it was kicked, search your library for a Rebel permanent card with mana value X or less, put it onto the battlefield, then shuffle.

Other creatures you control get +1/+1.
When Kotis, Promised General dies, you may return it to its owner's hand.

Whenever you cast a creature spell, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Whenever you sacrifice an Idol, draw a card.

Archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Sacrifice a land: Put a card from the archived library into your hand.

[+2]: Look at the top card of your library. If it's a permanent card with mana value less than the number of lands you control, you may put it onto the battlefield.
[–1]: Sacrifice a land. If you do, draw three cards.
[–7]: Destroy up to X target permanents, where X is the number of lands you control.

Art of war — At the beginning of your end step, if Kowareta Scrounger dealt damage to an opponent this turn, you may search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Haste
When Kragnoss, Rebellion Commander enters, create a 1/1 red Goblin creature token.
Whenever a Goblin you control attacks, Kragnoss, Rebellion Commander deals 1 damage to target creature defending player controls.

Flying
Whenever an opponent discards a card, you may exile it. If you do, create a 1/1 black Bird creature token with flying and “This creature can't block.”
{B}, Sacrifice three Birds: You may cast a card exiled with Krahen, Dusk's Call without paying its mana cost.

Menace
When this creature dies, create two tapped 3/2 colorless Eldrazi creature tokens. Put a stun counter on one of them.