msem-instigator

Trample
Whenever you cast a noncreature spell, crystallize. If you create a Treasure this way, Heartforge Savant deals 1 damage to you for each Treasure you've created this turn. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Flying, vigilance, deathtouch, lifelink

At the beginning of your upkeep, if you have less life than an opponent, you lose 1 life and you draw a card.

Deathtouch
Whenever another creature dies, its controller discards a card at random.

Augmented — Whenever you cast a spell from your hand, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, exile cards from the top of your library until you reveal a nonland card with mana value less than that spell's mana value. You may cast that card without paying its mana cost. Put the revealed cards not cast this way on the bottom of your library in a random order.

Enchant creature
When Heartstrings leaves the battlefield, exile enchanted creature.
Whenever enchanted creature attacks or blocks, exile it at end of combat.

Shuffle your library, then reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order. Heathen Rise deals damage to you equal to the number of cards revealed this way.
Ferocious — That creature gains haste if it has power 4 or greater.

At the beginning of your upkeep, if each opponent controls more lands than you, search your library for a basic land card, reveal it, and put it into your hand, then shuffle.

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

Flying, lifelink

Choose a nonland permanent type. Destroy all permanents of the chosen type. Each player who controlled a permanent destroyed this way draws a card.

{2}{G}: Exile up to three cards from graveyards. Autocrat X, where X is the number of cards exiled this way. (If you don't control an autocrat, put X +1/+1 counters on this. It becomes an autocrat until it has no +1/+1 counters on it.)
Whenever Hegemony Monarch attacks, you may exile target card from a graveyard. If you do, untap it and it gains trample until end of turn.

Whenever you cast a spell with two or more black mana symbols in its mana cost, you draw a card and you lose 1 life.

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.

{T}, Pay 1 life: Add {U} or {R}.
{1}, {T}, Sacrifice Heist Headquarters: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

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.

Flying
When Helar Ritualist enters or whenever you cast a spell, if {W}{B} was spent to cast it, each opponent loses 3 life and you gain 3 life. Put a +1/+1 counter on Helar Ritualist.

Flying, lifelink
When Helar's Herald dies, target opponent may give themselves two poison counters. If they do, return Helar's Herald to its owner's hand. Otherwise, return Helar's Herald to the battlefield tapped under its owner's control.

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Creatures you control gain indestructible until end of turn. If this spell's tithe was paid, put a +1/+1 counter on each creature you control.

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.

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, lifelink, haste
At the beginning of the end step, sacrifice Helix Entity.

Choose five target cards in your graveyard. An opponent separates those cards into two piles. Put one pile into your hand and exile the other. Exile Hell or High Water.

Target opponent may have you draw X cards. If they don't, reveal the top X cards of your library. Hell's Verdict deals damage to that player equal to the total mana value of cards revealed this way.

Hellfire Caverns enters tapped.
{T}: Add {R}.
{2}{R}: Until end of turn, Hellfire Caverns becomes a 3/3 Devil creature with menace. Activate only if you're horrific.