Augusta, Order Returned

Flying, vigilance
Whenever Augusta attacks, each player exiles a card from their graveyard. When one or more nonland cards are exiled this way, put that many +1/+1 counters on target attacking creature.

Ceaseless Conflict

Spirit

Destroy all creatures. Then create a 3/2 red and white Spirit creature token for each nontoken creature you controlled that was destroyed this way.

Eiganjo Dynastorian

Vigilance
Whenever you attack with two or more creatures, this creature becomes prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Replenish

Return all enchantment cards from your graveyard to the battlefield.

Eiganjo Dynastorian // Replenish

Forum Filibuster

Inkling

At the beginning of your upkeep, create a 2/1 white and black Inkling creature token with flying. When you do, return up to one target Aura or Equipment card from your graveyard to the battlefield attached to that token.

Herald of Amity

Flying
When this creature enters, exile the top eight cards of your library. You may cast an Aura spell from among them without paying its mana cost. Then put the rest on the bottom of your library in a random order.
Whenever this creature attacks, it gets +X/+X until end of turn, where X is the number of Auras you control.

Vanguard of the Restless

Flying
Spirits you control get +1/+1 for each time you've cast your commander from the command zone this game.
Whenever a Spirit you control enters, you may pay {2}{W}. If you do, return this card from your graveyard to the battlefield.

Abstract Performance

Exile the top four cards of your library in a face-down pile, then exile the top four cards of your library in a face-up pile. An opponent chooses one of those piles. Put that pile into your graveyard. Look at the cards in the other pile. You may cast a spell from among them without paying its mana cost. Put the rest into your hand.

Dirgur Focusmage

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell with mana value 5 or greater from your hand, this creature becomes prepared.

Braingeyser

Dirgur Focusmage // Braingeyser

Expansion Algorithm

Proliferate X times. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there.)

Quintorius, History Chaser

Whenever one or more cards leave your graveyard, create a 3/2 red and white Spirit creature token.
+1: You may discard a card. If you do, draw two cards, then mill a card.
−4: Spirits you control gain double strike and vigilance until end of turn.
Quintorius, History Chaser can be your commander.

Leitmotif Composer

Copy

Whenever this creature deals combat damage to a player, draw a card.
Whenever you cast an instant or sorcery spell with mana value 5 or greater, create a token that's a copy of this creature.
{2}{U}: Creatures named Leitmotif Composer can't be blocked this turn.

Nexus Mentality

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Move all counters from target nonland permanent you control onto another target nonland permanent you control.
• Remove all counters from target nonland permanent you control. Draw a card for each counter removed this way.

Owlin Spiralmancer

Flying, vigilance
Whenever you cast your first spell with {X} in its mana cost each turn, you may copy it. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Changing Loyalty

Flash
Replicate {2} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies. Copies become tokens.)
Enchant creature
When enchanted creature dies, return it to the battlefield under your control.

Coercive Impetus

Enchant creature
Enchanted creature gets +1/+1 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you draw a card and lose 1 life.

Defiling Daemogoth

Menace
Whenever a creature you control deals combat damage to a player, you gain 1 life.
At the beginning of your end step, each opponent loses X life, where X is the amount of life you gained this turn.

Secrets of Strixhaven Commander