msem-instigator

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.

Indestructible
You have no maximum hand size.
Whenever an opponent draws a card, you draw a card.
If you would lose the game other than for having 0 or less life, you win the game instead. (Another player winning the game does not cause you to lose the game.)

Flying
When Krothuss, Abyssal Terror dies, return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.
Foreshadow {6}{U}{U} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

Flying, ward {2}
At the beginning of your upkeep, if Mirrorwing Commander is embattled, create a token that's a copy of it. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Spells your opponents cast that target Onigori, Ema's Shield cost {2} more to cast.
Whenever Onigori deals combat damage to a player, that player can't untap more than two permanents during their next untap step.

Flash
Flying, protection from sorceries
You may look at the top card of your library any time.
You may cast spells from the top of your library as long as it's not your main phase.

Flying
Whenever Rimebreath Tyrant attacks, you may discard a card. When you do, tap target creature. It doesn't untap during its controller's next untap step.

Flying, prowess
Once each turn, when you cast a noncreature spell, you may create a 4/4 blue Sphinx Wizard creature token with flying, then scry 1.
{2}{U}{U}, Discard Sage of the Hereafter: Create a 4/4 blue Sphinx Wizard creature token with flying, then scry 1. Activate only as a sorcery.

Flash
Satrapies you control have “{T}: Draw a card.”

Flying
When Scion of Torrents enters, you may return target nonland permanent to its owner's hand.
Whenever an Island you control enters, you may aetherize Scion of Torrents. (To aetherize, create a token that's a copy of it, then exile that token.)

Seaside Skimmer can't be blocked if you've cast a Dragon spell or Adventure spell this turn.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

{8}{U}{U}: Monstrosity 5. (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous.)
When Shipway Whale becomes monstrous, target player exiles all cards in their library, then shuffles their graveyard into their library.

Whenever Sunken One attacks, target creature defending player controls gets -13/-0 until end of turn.
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Flying
Spirited (When this creature enters, you may activate one of its activated abilities without paying its costs.)
Harmony — Draw three cards.
{2}{G}{G}: Harmonize. (Trigger up to one harmony of a permanent you control.)

Primal {2}{R}{R} (During your turn, you may cast this spell for {2}{R}{R} instead of playing a land.)
Flying, prowess
At the beginning of your end step, if you didn't cast a spell this turn, sacrifice Thunderstride.

Tyrant of the Depths has hexproof as long as it's untapped.
Whenever you cycle Tyrant of the Depths or it attacks, tap target nonland permanent you don't control and put a stun counter on it.
Basic landcycling {1}{U} ({1}{U}, Discard this card: Search your library for a basic land card, reveal it, and put it into your hand, then shuffle.)

Defender
Venerable Loremaster can attack as though it didn't have defender if it's in a pack. (Two or more creatures you control with equal power are in a pack.)

Whenever Waketide Serpent attacks, you may pay {2}{U}. If you do, tap target creature. It doesn't untap during its controller's next untap step.

Menace (This creature can't be blocked except by two or more creatures.)
When Achet-Aton, Living God enters, if your life total is less than 5, your life total becomes 5.
As long as you have 5 or more life, damage that would reduce your life total to less than 5 reduces it to 5 instead.

Whenever Battle-Scarred Combatant attacks or blocks, put a -1/-1 counter on it.

This spell costs {2} less to cast if you've cast a blue noncreature spell this turn. The same is true for a red noncreature spell.
Menace

When Corrupt Warden enters, up to one target creature gets -X/-X until end of turn, where X is the number of card types among cards in your graveyard.

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

Deathtouch
Cutthroat Deceiver enters with four -1/-1 counters on it.
{3}{B}, {T}: Move a -1/-1 counter from Cutthroat Deceiver onto another target creature.