msem-instigator

Whenever Herald of Purity is dealt damage, it deals that much damage to any target.
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.)

Whenever another nontoken creature you control dies, create a 1/1 green Saproling creature token.
{B}{G}, {T}, Sacrifice a creature: Return target permanent card from your graveyard to your hand.

Other Azra and Demons you control get +1/+1.
As long as you control three or more other Azra and/or Demons, Herald of Tamaak gets +1/+1 and has flying.

Rapport — Whenever Herald of the Hunt and at least one other creature you control become tapped, nourish 1. (To nourish 1, either put a +1/+1 counter on this creature or create a 1/1 white Citizen creature token.)

You may cast Heralds of Shikai from your graveyard as long as a creature an opponent controls died 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.

When Heretic's Vow enters, create two 1/1 white Cleric creature tokens with lifelink.
Once each turn, when you gain life, you may put a +1/+1 counter on target creature you control.

{B}{R}, {T}, Sacrifice Heretical Soulshifter: Return target creature card from your graveyard to the battlefield. It gains haste until end of turn. Activate only as a sorcery.

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

Hexproof, vigilance, lifelink

Deathtouch
Whenever a storied permanent you control enters, remove up to two counters from target creature or planeswalker an opponent controls. (Enchantments and legendary permanents are storied.)

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

Equipped creature gets +3/+1 and has haste.
Equip Soldier or Warrior {1}
Equip {4}

Choose two —
• Create two 1/1 white Soldier creature tokens.
• Creatures you control get +1/+1 until end of turn.
• You gain 5 life.
• Choose a creature. It gains indestructible until end of turn.

Colossal 2—{6}{W}{W} (You may cast this for its colossal cost to have it enter with two +1/+1 counters; or pay {6}{W}{W} as a sorcery: Put two +1/+1 counters on it if it has none.)
When Heroes' Adversary's colossal ability puts one or more counters on it, exile target creature an opponent controls until Heroes' Adversary leaves the battlefield.

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Draw a card.

Prowess
Whenever Hethwyr Warcaster or another Wizard you control enters, you may draw a card.

Flash
When Hexfang Ascetic enters, return target spell to its owner's hand.

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.

Scry 2, then create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Monument {2}{R} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Target creature gains flying and gets +1/+0 for each card in your hand until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

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.

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

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

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