msem-instigator

First mate—Your starting deck contains twelve or more creature cards and they all share a creature type. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
As Adam of the Ironside enters, choose a creature type. Adam becomes that type.
Adam gets +1/+1 for each other creature you control of the chosen type.

At the beginning of combat on your turn, up to one target artifact you control becomes a creature in addition to its other types and gains “This creature's power and toughness are each equal to the number of artifacts you control” and “{U}: Exile this creature, then return it to the battlefield under your control.”

Indestructible
Legendary permanents you control have indestructible.

{1}: Choose one. Activate only once each turn.
• Adaptive Servitor gets +1/+1 and gains first strike until end of turn.
• Adaptive Servitor gets +2/+0 and gains trample until end of turn.

Search your library for a creature card with mana value 3 or less, put it onto the battlefield, then shuffle. It gains haste until end of turn. Return it to your hand at the beginning of the end step.

{G}: Tap Adaptive Troll. It gains indestructible until end of turn.
At the beginning of each upkeep, if Adaptive Troll was dealt lethal damage last turn, put a counter of your choice on it from among vigilance, deathtouch, reach, trample, and +1/+1.

At the beginning of your upkeep, if you control four or more Swamps, you may exile target creature card from your graveyard. If you do, create a tapped token that's a copy of it except it's a black Mummy.

Flash
When Adiran Distractor enters, return up to one target creature you control and up to one target creature you don't control to their owners' hands.

{T}: Add one mana of any type that a land an opponent controls could produce.

As an additional cost to cast this spell, exile two permanent cards from your graveyard.
You may cast Adiran Survivors from your graveyard.

Menace
Whenever a creature an opponent controls dies, 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.”)

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Tap target creature and put two stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Flying, haste
Whenever Adoroth, the Baneful attacks, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)
{1}{R}{R}: Adoroth, the Baneful deals 4 damage to any target. Activate only if you have no cards in hand.

Advanced Powercell enters tapped.
{T}: Add one mana of any color.

Choose one —
• Create three X/X colorless Construct artifact creature tokens.
• Create X tokens that are copies of target artifact you control.

As an additional cost to cast this spell, discard a card.
Advent from Above deals 3 damage to any target. Exile the top two cards of your library. You may play those cards during any turn you attacked with an artifact creature.

As long as you control four or more differently named lands, creatures you control get +1/+1.
As long as you control a land named Far-Off Lands, creatures you control get +1/+1.

First strike
Whenever a player loses life, creatures you control get +1/+0 until end of turn.

{1}{W}: Aegis Champion gains indestructible until end of turn.

Rapport — Whenever Aelinn, Serpent's Voice and at least one other creature you control become tapped, reveal the top card of your library. You may cast that card. If you don't, put it into your graveyard and Aelinn, Serpent's Voice deals 2 damage to each opponent.

{T}, Discard a card: Draw a card from each of your libraries.
{1}{U}{R}, {T}, Discard your hand: Return each Study card from your graveyard to your hand.

Archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
You may play the top card of the archived library.
You can't play cards from your hand.

({T}: Add {U}.)
Aerie's Pillar enters tapped.
Flying
{2}{U}{U}: Aerie's Pillar becomes a creature in addition to its other types until end of turn.

Flash
When you cast Aether Ascendant, you may have it become a copy of target instant or sorcery spell. If you do, choose new targets for it. (It won't enter.)

Exile target creature, then return it to the battlefield under your control. Then sacrifice it.