msem-instigator

{6}: Until the next time this ability resolves, and as long as Helm of the Infinite and target creature you control are on the battlefield, each other creature is a copy of that creature, and effects that would cause permanents to become creatures cause them to become copies of that creature instead.

Whenever you lose 2 or more life during your turn, put two blood counters on Hemomancy.
{1}{B}, Remove X blood counters from Hemomancy: Return target creature card with mana value X from your graveyard to the battlefield.

At the beginning of each end step, if a creature died this turn, you may put a +1/+1 counter on target creature you control.

(Transform this if it's not attached to a creature. Pay {B} as a sorcery to unattach it.)
Enchant creature you control
Herald of Death's rider gets +1/+1.
Sacrifice a creature: Herald of Death's rider gets +2/+2 until end of turn.

Whenever you put a counter on another permanent you control, put a +1/+1 counter on Herald of Ruination. This ability triggers only once each turn.
Surpass {5}{G} ({5}{G}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Flying
{2}{W}, Sacrifice Herald of the Departed: Create two 1/1 white Spirit creature tokens with flying.

Haste
{1}{R}, {T}: Attacking creatures you control get +1/+0 until end of turn.

Haste
Whenever Herald of the Humble deals combat damage to a player, that player reveals the top card of their library. If it's a nonland card with mana value 3 or less, they may cast it without paying its mana cost.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever a creature deals combat damage to a player, if it was encouraged by Herald of the White Orchid this turn, create a 1/1 white Soldier creature token.

Put a +1/+1 counter on target creature you control. Prevent all damage that would be dealt to that creature this turn.

Beckon Ox {1}{W} ({1}{W}: This enchantment permanently becomes an Ox creature in addition to its other types.)
Vigilance
Whenever a creature or another enchantment you control enters, you gain 1 life.

(Transform this if it's not attached to a creature. Pay {4}{G} as a sorcery to unattach it.)
Enchant creature you control
Herdstrider's rider gets +1/+1 for each land you control and has trample.
Whenever Herdstrider's rider attacks, create an X/X green Elephant creature token with trample that's tapped and attacking, where X is that creature's power. Exile that token at the end of combat.

Heretic's Home enters tapped.
{T}: Add {R} or {G}.
When Heretic's Home enters, you may put a loyalty counter on a planeswalker you control.

When Hermetic Fisher dies, you may return target creature to its owner's hand.

Enchant creature or planeswalker
Enchanted permanent has base power 0 and loses all abilities.

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

Hibernation Den enters tapped.
{T}: Add {W}.
{W}, {T}: You gain 1 life. Activate only as a sorcery and only if you control a white creature.

{T}, Sacrifice Hidden Garden Entrance: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Monument {W}{U}{B}{R}{G} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

{T}, Pay 1 life: Add {G} or {U}.
{1}, {T}, Sacrifice Hidden Hollow: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

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.

Prowess
Whenever High Rollers Croupier attacks, you may put a lore counter on a Saga you control.

({T}: Add {R}.)
As Highland Dunes enters, you may pay 1 life. If you don't, Highland Dunes enters tapped.

Concord — Highland Hermit gets +1/+1 and has hexproof as long as there are four or more card types among permanents you control.

({T}: Add {R} or {G}.)
Highland Vale enters tapped.

Highpoint Shrine enters tapped unless you played it from exile.
{T}: Add {W} or {U}.