msem-instigator

When Gulchdrinker Serpent enters, detain target permanent. (Until your next turn, that permanent can't attack or block and its activated abilities can't be activated.)

{B}{G}{U}, Discard a card named Gusma, God of Creation: Gusma gains indestructible and becomes a God creature in addition to its other types.
Whenever Gusma enters or attacks, add {B}{G}{U} and draw a card. You don't lose this mana as steps, phases, and turns end.

At the beginning of combat on your turn, for each permanent type, aetherize up to one target permanent you control of that type. (To aetherize, create a token that's a copy of it, then exile that token.)

Whenever H.S.S. Demeter becomes blocked by a creature, gain control of that creature.
Whenever H.S.S. Demeter deals combat damage to a player, draw two cards.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

Whenever Halford enters or attacks, an opponent chooses one. When they choose one that has already been chosen, copy that ability.
• That opponent loses 2 life and you gain 2 life.
• That opponent sacrifices a permanent.
• That opponent discards a card. If they can't, draw a card.

Hexproof
Deploy 4 (As this enters, you may tap any number of other creatures you control with total power 4 or more.)
When Hamlet Witch enters deployed, return target card from your graveyard to your hand.

Flying
Whenever Hao'Tai deals combat damage to a player, that player exiles the top five cards of their library and separates them into two piles. Put an ember counter on each card in the pile of your choice. You may play cards from exile with ember counters for as long as they remain exiled.

Flying
At the beginning of your first main phase, you may put any number of land cards from your hand onto the battlefield, then draw a card for each land put onto the battlefield this way.

Trample
Other Dwarves and Elves you control get +1/+1.
If Harl and Finn or another Dwarf or Elf you control entering the battlefield or attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Defender
Civilized — As long as you control an artifact, a creature, and an enchantment, Hauling Hippopotamus can attack as though it didn't have defender.

{W}: Target creature assigns combat damage equal to its toughness rather than its power this turn.

At the beginning of each player's upkeep, sacrifice Hayuan, the Misjudged if that player controls a creature with power 2 or less.
When Hayuan dies, create X Idol tokens, where X is the number of creatures you control. (They're artifacts with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Menace
At the beginning of your end step, He of All Hallow's Eve deals damage equal to its power to you unless you're horrific. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

Flying
If a source without flying would deal damage to you, prevent 2 of that damage.
Crew 5

Tap up to two target creatures.
Coalesce {5}{W}{W} (You may cast this from your graveyard for {5}{W}{W}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Heavens Claim Their Due enters tapped.

Disgraced 5 (This enters with five -1/-1 counters. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)
Prevent all combat damage that would be dealt to Heir Unapparent.

Colossal 5—{8}{W}{W} (You may cast this for its colossal cost to have it enter with five +1/+1 counters; or pay {8}{W}{W} as a sorcery: Put five +1/+1 counters on it if it has none.)
Ward {5}
When Hekaton Dismantler's colossal ability puts one or more counters on it, tap each creature you don't control. Those creatures don't untap during their controller's next 100 untap steps.

Trample
Resolute — At the beginning of combat on your turn, if Helicos Gargantua's power is greater than its base power, double its power until end of turn.

Indestructible
As long as your devotion to white is less than five, Heliod isn't a creature.
If an effect would create one or more kinds of tokens under your control, it creates an additional token of each kind.
{3}{W}: Put a +1/+1 counter on each other creature you control. Activate only as a sorcery.

This spell costs {X} less to cast, where X is your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)
Trample

Trample
Whenever Hellfire Titan enters or attacks, exile the top card of your library and up to one target instant or sorcery card with mana value 3 or less from your graveyard. Until the end of your next turn, you may play those cards.

Flying
If a source would deal damage to an opponent, it deals double that damage to that player instead.

Flying
Whenever Hellkite Omnivore attacks, you may have it consume. If you do, put a +1/+1 counter on Hellkite Omnivore. When a creature is sacrificed this way, Hellkite Omnivore deals 3 damage to any target. (To consume, sacrifice another creature or exile a creature card from your graveyard.)

Whenever a nontoken creature you control dies, create a 1/1 colorless Spirit creature token with flying.

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