msem-instigator

Flying, prowess
When Chronosphere Sovereign enters, nonbasic permanents target opponent controls don't untap during their controller's next untap step.
When Chronosphere Sovereign dies, it deals 3 damage to each tapped creature you don't control. Destroy each tapped artifact you don't control.

When Churning Spellroot enters, create three 1/1 black Worm creature tokens.

This spell costs {1} less to cast for each creature you attacked with this turn. (Those creatures don't have to still be on the battlefield.)
Flying

Trample
Colossal Greatwurm enters with five +1/+1 counters on it.
Whenever a player draws a card, put a +1/+1 counter on Colossal Greatwurm.
Remove three +1/+1 counters from Colossal Greatwurm: Create a 3/3 green Wurm creature token.

Concord — When Coral Bruiser enters, if there are four or more card types among permanents you control, put target creature you don't control into its owner's library third from the top.

When Core Paradigm enters, conjure five cards named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)
Up to three times each turn, you may cast a sorcery spell without paying its mana cost.

This spell costs {1} less to cast for each card type among cards in your graveyard.
Deathtouch

Return each card with a cycling ability from your graveyard to your hand. You may cast any number of nonland cards with total mana value X or less from your hand without paying their mana costs, where X is the number of Satrapies you control.

When Crux Pinnacle enters, for each color, exile up to one target permanent of that color until Crux Pinnacle leaves the battlefield.
Whenever a player casts a spell, if there are five or more spells on the stack, you win the game.

Enchant player
When Curse of Fangs enters, gain control of target creature enchanted player controls. It becomes a Vampire in addition to its other types.
Creatures attacking enchanted player have lifelink.

Vigilance
This spell costs {1} less to cast for each +1/+1 counter among creatures you control.

This spell costs {2} less to cast for each creature that died this turn.
Flying, trample

Menace
When Depraved Archknight enters, each opponent may pay 7 life. For each player that doesn't, you draw seven cards.

Converge — Dirty-Pawed Grazer enters with a +1/+1 counter on it for each color of mana spent to cast it.
Dirty-Pawed Grazer can't be blocked by creatures with power 2 or less.

Flying
Div of the Endless Thought has all activated and triggered abilities of all other permanents on the battlefield.

Flying
When Djinn of the Twisted Wish enters, it deals 5 damage to up to one target creature or battle.

Pressure {3}{U}{B} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Destroy up to one target creature. Return all other nonland permanents to their owners' hands.

Flying, menace
When Dreadfire Tyrant enters, target opponent reveals their hand. You may put a creature or planeswalker card from it onto the battlefield under your control. That permanent gains haste and “At the beginning of your end step, sacrifice a permanent you control.”
When Dreadfire Tyrant dies, each opponent loses 5 life. You gain life equal to the life lost this way.

Target player draws a card for each card in their graveyard.

This spell costs {1} less to cast for each noncreature, nonland permanent you don't control.
When Earthform Pachyderm enters, destroy target noncreature, nonland permanent. Its controller creates a 3/3 green Elephant creature token.

Flying, vigilance, lifelink
Embodiment of Law enters with an indestructible counter on it.
{5}{W}{W}, Remove an indestructible counter from Embodiment of Law: For each permanent type, exile up to one permanent of that type.

Sacrifice a land: You may cast a spell from your hand without paying its mana cost. Activate this ability only once each turn.
Exile five land cards from your graveyard: Draw five cards. Exile the top ten cards of your library.

Deathtouch, lifelink
When Emperor Azuma Hashiro enters, gain control of target creature for as long as you control Emperor Azuma Hashiro.
At the beginning of your upkeep, each opponent loses life equal to the number of permanents you control but don't own.

Draw four cards.
Metamorph {3}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up and cast it at any time for its metamorph cost.)

As an additional cost to cast this spell, you may tap
any number of untapped Angels and/or Nephilim you control. This spell costs {1} less to cast for each creature tapped this way.
Flying, vigilance
When Empyrean Scholar enters, each creature tapped to pay its additional cost becomes a 4/4 Angel creature with flying and vigilance. (This effect lasts indefinitely.)