msem-instigator

Whenever you cast a spell that's white, blue, black, or green, put a +1/+1 counter on Hesitant Vanguard.
Surpass {5}{R} ({5}{R}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Whenever you cast an instant or sorcery spell, each opponent loses 1 life and you gain 1 life.

As Hexplate Companion enters, choose a card name.
You and Hexplate Companion each have protection from the chosen card name.

Flash
Whenever another permanent dies, put a +1/+1 counter on Heyu.
{1}{G}: Heyu becomes a colorless Island land until end of turn.

When Hideaway Agent enters, gain control of target nonland permanent with mana value 3 or less for as long as you control Hideaway Agent.

At the beginning of your upkeep, if you control a legendary creature, you draw a card and you lose 1 life.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, you gain life equal to its mana value.

Flying
When High Spirits enters, target creature gains flying until end of turn.

Flash
Whenever you cast another spell with flash or an instant, put a +1/+1 counter on High Street Shadow.

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

Whenever Highland Elk deals damage to a creature, return that creature to its owner's hand (if it's still on the battlefield.)

Flying, lifelink

When Hila Okunos enters, look at the top six cards of your library. You may reveal an Aura or Aurashaper card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Whenever another nontoken Aura or Aurashaper you control enters, create a token that's a copy of it.

When Himari enters, put a +1/+1 counter on a creature you control.
Creatures you control with counters on them have base power and toughness 4/4 and have trample.

Reach
Art of war — At the beginning of your end step, if Hinode Ranger dealt damage to an opponent this turn, put a +1/+1 counter on it.

{2}{R}, {T}, Exert Hinterland Ritualist, Sacrifice another creature: Hinterland Ritualist deals damage equal to the sacrificed creature's power to any target. Activate only as a sorcery. (An exerted creature won't untap during your next untap step.)

When Hirukari's Immortal dies, if it didn't enter this turn, create a token that's a copy of it, except it has no mana cost.

When Hisana-no-Oni enters, gain control of target creature until Hisana-no-Oni leaves the battlefield.

Reach
When Hoarding Arachnid dies, draw a card.

When Hollowflesh Ghoul dies, create a 1/1 black Skeleton creature token.

Flying, deathtouch
Revive {3}{B} ({3}{B}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

{T}: Add {C}.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Vehicle becomes an artifact creature until end of turn.)

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever a creature you control blocks or becomes blocked, it gets +1/+1 until end of turn for each +1/+1 counter on it.

When Honored Retinue enters, choose a creature you control. You may search your library for a creature card with the same name as that creature, reveal it, put it into your hand, then shuffle.

Flying
Whenever a Harpy you control becomes the target of a spell, scry 1.