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.
Ajani, the Greathearted
$1.64
Creatures you control have vigilance.
+1: You gain 3 life.
−2: Put a +1/+1 counter on each creature you control and a loyalty counter on each other planeswalker you control.
Creatures you control have menace.
−2: Amass Zombies 2. (Put two +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)
Creatures you control get +1/+0.
+1: Add {R} or {G}. Creature spells you cast this turn can't be countered.
−2: Target creature you control fights target creature you don't control.
During your turn, Gideon Blackblade is a 4/4 Human Soldier creature with indestructible that's still a planeswalker.
Prevent all damage that would be dealt to Gideon Blackblade during your turn.
+1: Up to one other target creature you control gains your choice of vigilance, lifelink, or indestructible until end of turn.
−6: Exile target nonland permanent.
Each creature you control assigns combat damage equal to its toughness rather than its power.
−3: You gain life equal to the greatest toughness among creatures you control.
Whenever you cast or copy an instant or sorcery spell, Ral deals 1 damage to target opponent or planeswalker.
+2: Scry 1.
−2: When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
During your turn, creatures and planeswalkers you control have lifelink.
+2: Sorin deals 1 damage to target player or planeswalker.
−X: Return target creature card with mana value X from your graveyard to the battlefield. That creature is a Vampire in addition to its other types.