msem-instigator

Exile target nonland permanent if its mana value is less than or equal to the greatest number of nonland permanents controlled by a single player.

When Ideologize enters, exile target creature an opponent controls and each other permanent with the same name that player controls. When Ideologize is no longer on the battlefield, return a card exiled with it to the battlefield under its owner's control.

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Whenever Wild Lifescale attacks, proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Cast this spell only if you have 10 or less life or if you control six or more lands.
All creatures get -5/-5 until end of turn.

First strike, hexproof

Counter target noncreature spell unless its controller pays {2}.

At the beginning of your end step, put an encroachment counter on Approach of Old Lovi, then it deals X damage to any target and you gain X life, where X is the number of encroachment counters on Approach of Old Lovi.

Whenever you attack or cast a multicolored spell, put a +1/+1 counter on Brandy Axel.
If Brandy Axel would be destroyed, remove a +1/+1 counter from her. If you do, instead remove all damage from her and she deals 2 damage to each opponent.

Landfall — Whenever a land you control enters, 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.”)

When this creature enters, look at target opponent's hand. You may exile a nonland card from it. For as long as that card remains exiled, its owner may play it. A spell cast this way costs {2} more to cast.
Arise {2}{W}{W} ({2}{W}{W}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Whenever Andazir enters or transcends, each opponent sacrifices a nonland permanent.
{1}{B}{R}: Demon — Create four 1/1 black Snake creature tokens with deathtouch.
{2}{B}{R}: Elder — You draw three cards and you lose 3 life.

Flying, haste
Whenever Pyrus, the Undying Flame attacks, add {R}{R}{R}{R}. You don't lose this mana as steps, phases, and turns end.
{1}{R}: Pyrus gets +1/+0 until end of turn.

Whenever Culling Claw attacks, target creature gains winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)

Target creature or planeswalker you control explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 or loyalty counter on that permanent, then you may put that card into your graveyard.)

Aleud Beastmaster has frenzy X, where X is the number of unblocked attacking creatures you control. (Whenever it attacks and isn't blocked, it gets +X/+0 until end of turn.)

Attacking creatures you control have first strike.
Whenever Qulai, Orchard Guardian attacks or becomes the target of a spell or ability an opponent controls, conjure a card named Fox of the Orange Orchard into your hand. (It's a {1}{W} 3/1 Fox Spirit creature.)

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Create a 1/1 blue Pirate creature token or a 2/2 white Dwarf creature token.
III — Until end of turn, creatures you control gain “Whenever this creature attacks, draw a card, then discard a card unless this creature is a Pirate.”
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Temple Recluse gets +1/+0 as long as you've cast a noncreature spell this turn.

When Mul Daya Elder enters, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Whenever a land you control enters, put a +1/+1 counter on Mul Daya Elder.

If you would draw one or more cards, you may have each player draw an additional card.
Spells cost {1} less to cast if a player cast a spell this turn.

Flying
When Unfettered Atrocity enters, destroy target creature or planeswalker.

Enchant creature
Enchanted creature gets +3/+0 and has trample.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Flying
Dragon spells and Adventure spells you cast cost {1} less to cast.

Converge — Gain control of up to X target creatures with total mana value X or less, where X is the number of colors of mana spent to cast Alive and on Top.

[+1]: Creatures you control gain deathtouch until end of turn.
[–1]: Each player loses 3 life unless they discard a card or sacrifice a creature.
[–6]: You get an emblem with “You may play permanent cards from your opponent's graveyards, and you may spend mana as though it was mana of any color to do so.”