Given the rarity and limited information on some bonus cards, this may not be a complete list of all potential bonus cards available in this Secret Lair.
Hedron Archive
{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.
A deck can have any number of cards named Shadowborn Apostle.
{B}, Sacrifice six creatures named Shadowborn Apostle: Search your library for a Demon creature card, put it onto the battlefield, then shuffle.
As this artifact enters, look at an opponent's hand, then choose any card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.
Fading 4 (This artifact enters with four fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
At the beginning of each player's upkeep, that player taps an untapped artifact, creature, or land they control for each fade counter on this artifact.
