mtg a deck can have any number of cards named o:"a cards" · Scryfall Magic: The Gathering Search Ancestor's Souls - White "A

When it enters the battlefield, it gives a creature -13/-13 until the end of the turn, which is great

1 Lucius the Eternal 1 Magnus the Red 1 Pink Horror 1 Heralds of Tzeentch 1 Noise Marine 1 Bituminous Blast 1 Deny Reality 6 (9) 1 Be'lakor, the Dark Master 1 Mortarion, Daemon Primarch 1 Bloodthirster 1 Keeper of Secrets 1 Let the Galaxy Burn 1 Drach'Nyen 1 The Horus Heresy 1 Mutalith Vortex Beast 1 Warstorm Surge 7 (1) 1 Lord of Change 8 (1) 1 Decree of Pain 9 (1) 1 Blasphemous Act 11 (1) 1 Blood for the Blood God

As it stands, this a miss on reprint value

Kaya, Spirits Justice Kaya, Spirits' Justice can drop, exile your Cityscape Leveler from your graveyard (while also surveilling 2) and turn a Clue or Food token, not just a thopter or spirit into a copy of it that flies

The irony is that there Magic has no shortage of good blue and black creatures