Mirror-Sigil Sergeant

Trample
At the beginning of your upkeep, if you control a blue permanent, you may create a token that's a copy of this creature.

Fleet Swallower

Whenever this creature attacks, target player mills half their library, rounded up.

Bruna, Light of Alabaster

Flying, vigilance
Whenever Bruna attacks or blocks, you may attach to it any number of Auras on the battlefield and you may put onto the battlefield attached to it any number of Aura cards that could enchant it from your graveyard and/or hand.

Traumatize

Target player mills half their library, rounded down.

Mirror-Mad Phantasm

Flying
{1}{U}: This creature's owner shuffles it into their library. If that player does, they reveal cards from the top of that library until a card named Mirror-Mad Phantasm is revealed. The player puts that card onto the battlefield and all other cards revealed this way into their graveyard.

Cephalid Vandal

At the beginning of your upkeep, put a shred counter on this creature. Then mill a card for each shred counter on this creature.