A series of what appears to be Mystical Archive-themed Secret Lair cards has emerged on Magic Online after an update to the client yesterday.
The six cards, which appear to be All is Dust, Artifact Mutation, Drown in the Loch, Fire Covenant, Fractured Identity, and Fracturing Gust, are each done in the same design style as other cards from the Mystical Archive, and each feature the same star symbol that other Secret Lair drops have used in the past.
Wizards of the Coast (WotC) hasn’t confirmed the drop yet.