msem-instigator

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.

{T}: Add one mana of any color. When you spend this mana to cast a spell with mana value 5 or greater, put two +1/+1 counters on Herald of the New Divinity.

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

(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.

Target opponent may draw two cards. If they do, you draw four cards. Otherwise, you create four 1/1 red Elemental creature tokens.

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.

{1}{U}, {T}: Reveal the top card of your library. If it doesn't share a color with Heretical Seer, put it into your hand.

For each color among nontoken permanents you control, add one mana of that color.

Target player sacrifices any number of lands. That player searches their library for up to that many land cards, puts them onto the battlefield tapped, then shuffles.
Fabled {5}{G}{G} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that player.)

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

You may have Hero of Shengin Province assign its combat damage as though it weren't blocked.
{2}{G}: Until end of turn, you may have creatures you control assign combat damage as though they weren't blocked. Activate only if Hero of Shengin Province is in your graveyard.

Vigilance
Concord — {G}: Hero of the Stained Blade gets +2/+2 and gains trample until end of turn. Activate only if there are four or more card types among permanents you control and only once each turn.

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

Search your library for a basic land card and put it onto the battlefield, then shuffle. Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

{T}: Add one mana of any color.
{7}, {T}, Sacrifice Hero's Statue: Draw three cards.

[+1]: Add {G}{U}{R}. Spend this mana only to cast creature spells.
[–2]: Reveal the top card of your library. If it's a creature card that costs less than the last spell you cast this turn, you may put it onto the battlefield. Otherwise, draw a card.
[–7]: Target creature becomes a legendary 20/20 green creature named Illusion of Kaur with hexproof and trample until end of turn.

At the beginning of your upkeep, put a charge counter on Hexstone.
{T}, Sacrifice Hexstone: Choose a nonland permanent type. Destroy each permanent of the chosen type with mana value less than or equal to the number of charge counters on Hexstone.

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

At the beginning of your upkeep, put a +1/+1 counter on Heyu, Immortal Hunter.
Whenever Heyu becomes the target of a spell or ability an opponent controls, counter it if Heyu has the greatest power among creatures on the battlefield.

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.

{1}{G}, Discard Hibiscus Snapdragon: Create a Treasure token.
Scavenge {4}{G} ({4}{G}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

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.)

{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.”)

Hidden Prowess deals 2 damage to target creature. When that creature dies this turn, create a 1/1 red Elemental creature token.