msem-instigator

Flying
Unveil {3}{W}{U} ({3}{W}{U}: Transform this. Unveil only as a sorcery.)

Flying, trample, haste
Dragons you control get +3/+3 as long as you control permanents with total mana value 20 or greater.
Whenever you spend five or more mana to cast a spell or activate an ability, create a 2/2 red Dragon creature token with flying.

Whenever a Hound you control is dealt damage, Greypelt Emissary deals 1 damage to any target.
Whenever Greypelt Emissary attacks, you choose how target creature blocks this combat.

Trample
Whenever this creature attacks, you may tap another untapped Dwarf or Elf you control. If you do, create a Treasure token.

Guide to the Wayward enters with a +1/+1 counter on it.
{1}{W/U}, {T}: Permutate. (You may remove a counter from a creature you control. If you do, put two +1/+1 counters on a different creature you control.)

At the beginning of combat on your turn, for each permanent type, aetherize up to one target permanent you control of that type. (To aetherize, create a token that's a copy of it, then exile that token.)

Flying
Whenever Haerthach, the Wight King deals combat damage to a player, you may sacrifice another creature. When you do, create a 1/1 white Spirit creature token with flying. Return the sacrificed card to the battlefield tapped and under your control at the beginning of the next end step.

Vigilance
The first instant or sorcery spell you cast each turn has conspire. (As you cast that spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)

If one or more counters would be put on a permanent you control, you may have that many counters plus one or that many counters minus one put on that permanent instead.

Trample
As an additional cost to cast creature spells, you may sacrifice a permanent. If you do, that spell costs {2} less to cast and that creature enters with an additional +1/+1 counter on it.

Trample
Other Dwarves and Elves you control get +1/+1.
If Harl and Finn or another Dwarf or Elf you control entering the battlefield or attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Double strike
When this creature enters, mill four cards. Put a creature card with power 2 or less from among the cards milled this way into your hand.

{1}, {T}, Move a -1/-1 counter from another creature onto Harried Apothecary: Each opponent loses 1 life and you gain that much life.

Flash
Flying
Whenever this creature attacks, other creatures you control with flying get +1/+0 until end of turn.

Whenever Haunted Prodigy attacks, you may tap target creature.
Unveil {2}{W}{U} ({2}{W}{U}: Transform this. Unveil only as a sorcery.)

Ward—Sacrifice a permanent.
Whenever a player sacrifices a permanent, put a +1/+1 counter on Hayat, Hungering Bakhtak.
Surpass {4}{B}{G} ({4}{B}{G}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

When Heedless Lovers enters, you may return target Citizen card from your graveyard to your hand.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

[+2]: Until end of turn, up to one target creature you control gets +3/+3 and gains trample and vigilance.
[–2]: Destroy target artifact, enchantment, or tapped creature.
[–3]: Create a 1/1 green Insect creature token, a 2/2 white Cat creature token, and a 3/3 red Ox creature token.
[–8]: Until end of turn, creatures you control get +X/+X and gain trample and vigilance, where X is the number of creatures you control.

Whenever you draw a card, put a +1/+1 counter on Highborn Meditant.

When Historiamancer enters, return target instant or sorcery card from your graveyard to your hand.

Trample
Hollow Survivor's power and toughness are each equal to the number of cards in your hand.
Whenever Hollow Survivor deals combat damage to a player, draw a card.

Hollowghast, the Iron Phantom enters with three +1/+1 counters on it.
If damage would be dealt to Hollowghast, prevent that damage. Remove a +1/+1 counter from Hollowghast.

At the beginning of your upkeep, put a crop counter on Homestead.
{G/W}, Remove a crop counter from Homestead: Put a +1/+1 counter on target creature.
{G/W}, Remove three crop counters from Homestead: Put a +1/+1 counter on each creature you control.

When Hooded Inquirers enters, draw two cards.

You may cast Hunter of the Moon-Serpent from your graveyard as long as you gained life this turn.