msem-instigator

{T}, Sacrifice Adaptive Terrains: Search your library for a basic land card and put it onto the battlefield tapped, then shuffle.

Flying
Whenever another creature you control enters, Adavene, Dean of the Arts deals 1 damage to each opponent.
Whenever a creature you control deals combat damage to a player, you may exile it, then return it to the battlefield.

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.

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

Haste
Whenever two or more creatures you control deal combat damage to a player, tap those creatures, then gain control of target creature you don't control until end of turn. Untap that creature. It gains haste until end of turn. After this phase, there's an additional combat phase.

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.

Look at the top three cards of your library. You may reveal a creature or land card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

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

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

({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.)

{T}, Sacrifice Aether Gateway: Create a tapped Plains token, Island token, Swamp token, Mountain token, or Forest token.

If a creature entering the battlefield under your control causes a triggered ability of that creature to trigger, you may exile it. If you do, that ability triggers an additional time.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Aether Recoverer envisions a creature card, return target noncreature card from your graveyard to your hand.

Flash
When Aethermancer's Familiar enters, at the beginning of the next end step, you may aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

Target player mills X cards, where X is the number of cards named Against the Waves in your graveyard. Draw a card, then conjure three cards named Against the Waves and shuffle them into your main library.

Flash
When Agent of Deception enters, counter target creature or planeswalker spell unless its controller pays {X}, where X is your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Deception {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Agent of Long Shadows deals combat damage to a player, you may put a Rogue card from your hand or graveyard onto the battlefield.

Deception {1}{B}
When Aguri, Shadow of Doubt enters, target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

{T}, Discard a card: Add {C}.
Whenever you discard one or more cards, you may pay {2}. If you do, draw a card.

[+1]: Aiel Tazan deals 2 damage to any target. Then she deals 2 damage to herself unless you have her deal 2 damage to you.
[–3]: Creatures you control get +2/+0 and gain haste until end of turn.
[–X]: Create an X/1 red Elemental creature token with haste and trample. Exile that token at the beginning of the next end step. If X is 6 or more, it gains double strike.

Trample
When Ainok Scout enters, nourish 2, then return a creature you control to its owner's hand. (To nourish 2, either put two +1/+1 counters on this creature or create two 1/1 white Citizen creature tokens.)

As long as Ajani Enlightened has an odd or even number of loyalty counters on him, he has protection from mana values of that quality.
[+1]: Any number of players may draw a card. You may put a loyalty counter on Ajani Enlightened for each opponent that does.
[0]: You gain 2 life. Untap up to two target lands.
[–8]: Choose odd or even. You get an emblem with “You have protection from mana values of the chosen quality.”

[+1]: Distribute two +1/+1 counters among up to two target creatures. You gain 2 life.
[–1]: Create a 2/2 green Cat Warrior creature token.
[–3]: Exile target creature. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.
[–7]: You get an emblem with “Creatures you control get +X/+X, where X is your life total.”