msem-instigator

Double strike
Engage (This creature must be blocked each combat if able.)
{1}{R}: Balanced Blade gets +1/+0 until end of turn.

Whenever another nontoken creature you control dies, create a 1/1 black Rat creature token with “This creature can't block” if this is the first time this ability has resolved this turn. Otherwise, Ffion, Famine Warcaller deals 1 damage to each player.

Whenever Hero of Aer attacks, it gets +2/+1 until end of turn.

First strike, haste
Whenever Kragnoss' Battlecharger attacks, it gets +1/+0 until end of turn for each attacking creature.

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.)
When Painwield Explorer dies, it deals damage equal to its power to target player or planeswalker.

Haste (This creature can attack and {T} as soon as it comes under your control.)
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

When Seishin Smokeshaper enters, create a 2/2 colorless Spirit creature token.
Whenever you cast a noncreature spell, colorless creatures you control get +1/+1 until end of turn.

Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)
{1}{W}: You gain life equal to Sunken Outcast's power.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
When Worried Vulpine has three or more +1/+1 counters on it, remove them all and transform it.

{T}: Add one mana of any color a basic land you control could produce.

When Captured Mind dies, create a 3/3 white Construct enchantment creature token.

Trample
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.)

Whenever another creature you control dies, put a +1/+1 counter on Deathfeeder.
Sacrifice Deathfeeder: Target creature gets +X/+X until end of turn, where X is Deathfeeder's power.

Whenever another creature you control enters, you may change Declan, Wayward Squire's base power and toughness to that creature's power and toughness until end of turn.

{2}{G}, Sacrifice Derrivan Beast Tracker: Create a 3/3 green Beast creature token.

{T}: Add {G}.
{B/G}, {T}: Exile target card from a graveyard. If that card is a creature card, put a +1/+1 counter on Dovon, Verdant Experimenter and you gain 1 life.

When Familial Matriarch enters, nourish 2. (To nourish 2, either put two +1/+1 counters on this creature or create two 1/1 white Citizen creature tokens.)

{T}, Sacrifice another permanent: Add one mana of any color.
At the beginning of your end step, if you're horrific, put a +1/+1 counter on target creature. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
{T}: Add {G}.
Whenever Hierarch Ranger encourages a creature, add one mana of any color.

{T}: Add one mana of any color.

{T}: Add {C}.
Whenever you tap Masamori Initiate for mana, you may mill a card.

When Nitrous Renewer enters, you may put a land card from your hand onto the battlefield tapped.
{3}{G}, Exile Nitrous Renewer from your graveyard: Return target land card from your graveyard to your hand. Activate only as a sorcery.

{T}: Add {G}. If you control an attacking creature, add one mana of any color instead.

{T}: Add one mana of any color. Spend this mana only to cast a creature spell or activate an ability of a creature.
{5}{W}{U}{B}{R}{G}, Sacrifice Osk, the Maker's Pet: Create Osk Awakened, a legendary 20/20 green Squirrel God creature token with hexproof, trample, and indestructible.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever Primal Ruffian attacks, if it has a +1/+1 counter on it, other creatures you control get +1/+1 until end of turn. (If it had no counters on it when it attacked, this ability does not trigger.)