msem-instigator

Choose two —
• Tap target creature.
• Untap target creature.
• Draw a card.

When you cast Aspect of Shifting Storms, create a token that's a copy of it.
You may have Aspect of Shifting Storms enter as a copy of any creature on the battlefield, except if it's a token it has no mana cost.

When Asphodel Gravedealer dies, choose one —
• Put a +1/+1 counter on target creature you control.
• Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Whenever a storied permanent you control enters, tap target creature an opponent controls. (Enchantments and legendary permanents are storied.)

Aspiring Dragon has flying and haste as long as you control another Dragon.
{2}{R}{R}: Aspiring Dragon gets +3/+0 until end of turn.

Rhapsody {3}{W}{W} (Pay {3}{W}{W} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Lifelink

Whenever Aspiring Hero attacks alone, put a +1/+1 counter on it.
When Aspiring Hero dies, each opponent gains life equal to its power.

When you cast your third noncreature spell each turn, transform Aspiring Rascals.

Creatures with power greater than Aspiring Recluse's can't block it.
Whenever Aspiring Recluse deals combat damage to a player, you may pay {2}. If you do, transform it.

Vanguard — Whenever a creature you control attacks alone, it gets +1/+1 until end of turn.

Flash
When Assassin of Fahrib enters, choose one —
• Destroy target creature that was dealt damage this turn.
• Scry 2.

Equipped creature gets +1/+0 and has deathtouch and “{T}: This creature deals 1 damage to target creature you don't control. Sacrifice Assassin's Shuriken.”
Equip {2}

Target creature gets -3/-0 until end of turn. That creature's controller mills six cards.

Destroy target tapped creature.

Destroy target creature. Create a tapped Treasure token.

Recruit X times. You lose X life. (To recruit, create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Target player sacrifices an attacking creature.
Bulwark — That player sacrifices two attacking creatures instead if you control a creature with toughness 4 or greater.

Create three 1/1 colorless Construct Actor creature tokens.

Target creature gets -5/-0 until end of turn. Adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)

Menace
Once during each of your turns, when you sacrifice a permanent, you may put a +1/+1 counter on Assimilated Runner.

When Assurance of Finality enters, you may discard a card. If you do, draw two cards.
{1}, Sacrifice Assurance of Finality: Creatures you control gain haste until end of turn.

At the beginning of your upkeep, if the number of permanents you control, the number of cards in your hand, and the number of cards in your graveyard are all equal, you win the game.

First strike
Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Put a +1/+1 counter on each of up to two other target creatures you control.
[Lore III] Remove all lore counters from Astral Capricine. Create two 0/1 white Goat creature tokens.

Menace
Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Exile the top card of your library. You may play that card this turn.
[Lore III] Remove all lore counters from
Astral Cerberus. It deals 3 damage to up to one target creature.

Whenever you cast a spell, put a charge counter on Astral Dynamo.
{T}, Remove any number of charge counters from Astral Dynamo: Add that much {C}.