msem-instigator

Target creature gets +1/+1 until end of turn.
Fabled {2}{R/W}{R/W} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

First strike
Art of war — At the beginning of your end step, if Teikoku Cavalry dealt damage to an opponent this turn, put a +1/+1 counter on it.

Equipped creature has indestructible as long as it's tapped.
Equip {3}

Enchant player
Enchanted player may play an additional land on each of their turns.
Enchanted player may play lands from their graveyard.

This spell costs {1} less to cast for each creature you control that's in a pack. (Two or more creatures you control with equal power are in a pack.)

Flying
Morph {4}{W}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Ishim of Oblivion is turned face up, put a +1/+1 counter on it, then destroy target noncreature, nonland permanent.

Flying, vigilance
At the beginning of your end step, return up to one target permanent card from your graveyard to the battlefield with an indestructible counter on it.

Creatures you control named Colocolo can't be blocked and have ward {2}.
{U}{U}: Put an inspiration counter on target creature. It's named Colocolo in addition to its other names for as long as it has an inspiration counter on it.

Whenever you cast a nonblue spell, create a 1/0 blue Horse Nymph creature token.
Horses get +1/+1 and have flying.

Enchant creature
Whenever enchanted creature attacks, put a -1/-1 counter on it.

Untap all permanents you control during each other player's untap step.

Flying
Cruel Fledgling enters with a +1/+1 counter on it if six or more cards are in your graveyard.

When Ragantiar enters, mill five cards.
{3}{B}, Sacrifice a creature: Return target creature card with power X or less from your graveyard to the battlefield, where X is 1 plus the sacrificed creature's power.

[+1]: Create a token that's a copy of another target permanent. Exile that token at the beginning of your next upkeep.
[–3]: If it's not an extra turn, you take an extra turn after this one, then skip your next turn that's not an extra turn.
[–6]: Until end of turn, planeswalkers become copies of I, Queen of Eons, except they aren't legendary. Destroy all nonland, non-I permanents.

Destroy target creature. You lose 4 life.

Concord — When Riptide Mystic enters, if there are four or more card types among permanents you control, you may return target nonland permanent to its owner's hand.

When Howler Sellout enters, for each creature that died this turn, post a bounty on up to one target creature an opponent controls. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

{T}: Add {C}.
{1}, {T}, Sacrifice War-Torn Tundra: Arm target creature you control. Activate only as a sorcery. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Once each turn, when you foretell a card or cast a foretold spell, you may create a tapped Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Prowess
Whenever Steamwalker attacks, you may discard a card. If you do, draw a card, then catalyze. (The next spell you cast this turn costs {1} less to cast.)

When Sealed Riftway enters, exile up to one target card from a graveyard.
{2}, {T}, Sacrifice Sealed Riftway: Exile target player's graveyard. Draw a card.

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, Regrets of Mortals gets +2/+0 until end of turn. You may discard a card. If you do, draw a card.

At the beginning of each opponent's upkeep, that player may discard their hand. If the player does, sacrifice Under the Gun. Otherwise, put a bullet counter on Under the Gun, then that player loses life equal to the number of bullet counters on it.

Flying, deathtouch
Once each turn, when you cast a spell from your graveyard, you may cast target card in your graveyard with lesser mana value than that spell without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Each opponent loses 1 life. Whenever you cast another spell this turn, each opponent loses 1 life.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)