msem-instigator

Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)
Other creatures you control have infiltrate.

Equipped creature has “{T}: Target attacking creature gets +1/+1 until end of turn.”
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Equipped creature has base power and toughness 4/4, haste, and hexproof.
Equip {2}

{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.

Equipped creature can't attack or block.
{4}: Attach Heping's Armistice Chains to target creature you don't control.
{8}: Gain control of equipped creature.

[+1]: Until your next turn, if a source would deal damage to Heping, Master Arbitrator, prevent all but 1 of that damage.
[–2]: Create a white Aura enchantment token named Pacifism attached to target creature an opponent controls. It has enchant creature and “Enchanted creature can't attack or block.”
[–8]: You get an emblem with “At the beginning of your end step, your life total becomes 20.”

Flying
Herald of Oblivion enters with X -1/-1 counters on it, where X is your life total.

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.)

Flying
Whenever Heroes of Wars Past attacks, attacking Human creatures get +1/+1 and gain flying until end of turn.

[+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 +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.

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

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.)

Whenever High-Priestess Nebti attacks or blocks, create a 2/2 white Cat creature token.
{1}{R}{R}, Tap an untapped Cat creature you control: That creature fights target creature you don't control.

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

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

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Hinasa Mystic enters, draw a card.

Whenever a player cycles a card, that player mills two cards.

When Hired Kalak enters, put target card from your graveyard on top of your library.

Flying
Whenever Hoff's Scout deals combat damage to a player, you may scry 1.

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

When Holy War enters, create three 1/1 white Cleric creature tokens.
Creature tokens you control have first strike and lifelink.

Target creature you control fights another target creature.
Inscribe {3}{G} ({3}{G}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

When Hooded Inquirers enters, draw two cards.

Flying
Morph {4}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When you turn Hopebringer Cherub face up, creatures you control get +1/+1 until end of turn.