msem-instigator

{1}, Sacrifice Aberrant Apostle: Choose one. This ability costs {1} less to activate as long as Aberrant Apostle entered this turn.
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Equipped creature has vigilance.
Equipped creature gets +3/+3 as long as you control a Spirit.
Equip {1}

Exile the top five cards of your library. You may put a creature card from among them with mana value 2 or less onto the battlefield.

Prevent all combat damage that would be dealt to and dealt by Bereaved Aristocrat.
Unveil {2}{W}{U} ({2}{W}{U}: Transform this. Unveil only as a sorcery.)

Ascend—{W}{B}, Discard a card, Sacrifice a creature, Exile a creature card from your graveyard. ({W}{B}, Discard a card, Sacrifice a creature, Exile a creature card from your graveyard: Exile this creature, then return it to the battlefield transformed. Ascend only as a sorcery.)

Vigilance
Unveil {2}{G}{W} ({2}{G}{W}: Transform this. Unveil only as a sorcery.)

Level experience (Whenever this creature attacks, if it has fewer than three level counters on it, put a level counter on it.)
When Copperhide Calf has three or more level counters on it, remove them all and transform it. [2/2]
[level 1-3] Prevent the first 1 damage that would be dealt to Copperhide Calf each turn. [3/3]

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Curious Cubs has first strike as long as its attacking.
When Curious Cubs has three or more +1/+1 counters on it, remove them all and transform it.

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Frontiers Anew {G}
Sorcery — Adventure
Search your library for a basic land card, reveal it, put it into your hand, then shuffle. (Then exile this card. You may cast the creature later from exile.)

Target creature gains indestructible until end of turn. Scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)
Fabled {3}{W} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Double strike

When Ethersketch Blueprints enters, create a 1/1 blue Thopter artifact creature token with flying.
{2}, Sacrifice Ethersketch Blueprints: Draw a card.
Monument {5}{B}{B} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)
Ascend {4}{W} ({4}{W}: Exile this permanent, then return it to the battlefield transformed. Ascend only as a sorcery.)

You can't lose the game until your next turn and your opponents can't win the game until your next turn.
Fuse (You may cast one or both halves of this card from your hand.)

Prevent all damage that would be dealt to target player this turn.
Fabled {1}{W}{W}{W} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that player.)

Whenever Haunted Prodigy attacks, you may tap target creature.
Unveil {2}{W}{U} ({2}{W}{U}: Transform this. Unveil only as a sorcery.)

Target creature gets +1/+3 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Vigilance

{1}, Tap an untapped creature you control: Leaping Dancer gets +0/+1 and gains flying until end of turn. Then if you've activated this ability three or more times this turn, transform Leaping Dancer.

Create a 1/1 white Bird creature token with flying. (Then exile this card. You may cast the creature later from exile.)

Ride {2}{W} ({2}{W}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Vigilance
Whenever Mikkino becomes blocked by a creature with power 3 or greater, exile that creature.

Noncreature spells your opponents cast cost {1} more to cast.
Unveil {2}{W}{U} ({2}{W}{U}: Transform this. Unveil only as a sorcery.)

{1}{W}: Target creature you control gets +0/+1 until end of turn and assigns combat damage equal to its toughness rather than its power this turn. When that creature deals combat damage to a player this turn, transform Reversal Medic.

Search your library for an Equipment card, reveal that card, put it into your hand, then shuffle.
Monument {3}{W} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Target creature gains indestructible until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)