msem-instigator

Prismatic — Whenever you cast a multicolored spell, you may discard a card. If you do, draw a card.

Flying, trample, haste
Dragons you control get +3/+3 as long as you control permanents with total mana value 20 or greater.
Whenever you spend five or more mana to cast a spell or activate an ability, create a 2/2 red Dragon creature token with flying.

Flying, trample
When Greedstoker Demon enters, you lose X life and create X Treasure tokens, where X is your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
You can't sacrifice more than one Treasure each turn.

Trample

Flash
This spell costs {1} less to cast for each creature that left the battlefield this turn.

Menagerie — When Grotto Guardian enters, if there are five or more creature types among creatures you control, target creature you don't control gets -2/-2 until end of turn.

Flying, haste
Whenever Guardian of the Devout attacks or blocks, other creatures you control gain indestructible until end of turn.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Gui can't attack or block unless you're in a renaissance.
{T}: Reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put it back on top or into your graveyard and you gain 3 life.

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.

Reach, trample
{1}{G}: You may remove a counter from a creature you control. If you do, tap that creature and it gains indestructible 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.

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
As an additional cost to cast creature spells, you may sacrifice a permanent. If you do, that spell costs {2} less to cast and that creature enters with an additional +1/+1 counter on it.

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.

When Helicos Aberration enters, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

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.

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.)

Flying, prowess
If you would draw a card, scry 1, then draw a card instead.
Whenever an opponent casts a spell, if it's not their turn, draw a card.

Flash
When Herald of Wisdom enters, you may cast target instant or sorcery card with mana value 4 or less from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

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

Trample, haste

Hurtling Swine attacks each combat if able.

Whenever IG-2 Disassembler enters or attacks, you may sacrifice an artifact. When you do, IG-2 Disassembler deals 2 damage to target player or planeswalker.