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.

Secret Lair Drop

Commander 2018

Flying, vigilance
Whenever Bruna, Light of Alabaster 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.

Avacyn Restored

Open the Helvault

All of these Auras will become attached to Bruna before combat damage is dealt. If Bruna is attacking, these Auras become attached before blockers are declared.

Only Auras that could legally enchant Bruna may be attached to it, whether they're being moved from other permanents or being put onto the battlefield. An Aura with "enchant land," for example, could not be attached to Bruna this way.