Spectral Cards are a form of consumable you can obtain during a run.
Spectral Cards are similar to Tarot Cards in the sense that they generally modify the playing cards in the deck as well, though to a much greater extent than Tarot Cards. In exchange for these large modifications, they usually disadvantage the player in another aspect of gameplay, such as reducing Hand Size, destroying additional cards or consuming all money. There are 18 different cards with no unlock conditions, but they can usually only be found in booster packs and not individually (unless with Ghost Deck). It is possible to spawn Spectral Cards via certain Jokers, or, in certain circumstances, purchase them in the shop, in which case they will take up a Consumable slot.
Add Foil, Holographic, or Polychromeedition (determined at random) to 1 selected card in hand.
Wraith
Creates a random RareJoker (must have room), but sets money to $0.
Sigil
Converts all cards in hand to a single random suit.
Ouija
Converts all cards in hand to a single random rank, but -1Hand Size.
Ectoplasm
Add Negative to a random Joker, but -1Hand Size, plus another -1 hand size for each time Ectoplasm has been used this run, e.g. using Ectoplasm 3 times in the same run decreases hand size by a total of 6 (1+2+3)
Immolate
Destroys 5 random cards in hand, but gain $20.
Ankh
Creates a copy of 1 of your Jokers at random, then destroys the others, leaving you with two identical Jokers. (Editions are also copied, except Negative)
Hex cannot be used when all your Jokers already have an Edition.
Wraith will always set your money to $0 even when in the negatives, removing the debt completely.
Aura has a 50% chance to make a card Foil, a 35% chance to make a card Holographic, and a 15% chance to make a card Polychrome. These are the same odds that The Wheel of Fortune has when upgrading a Joker when it triggers.
Because Ouija and Sigil converts every card in your hand, having a large hand size (ie. Turtle Bean) makes them substantially more powerful, while having a smaller hand size (ie. Stuntman) makes them less powerful.
Familiar will always create Kings, Queens, and Jacks, even if Pareidolia is equipped.
Trivia[]
The style of The Soul and Black Hole differs from other Spectral Cards, and resembles that of Tarot Cards and Planet Cards, respectively. This is consistent with how these cards have a low chance to appear in these Booster Packs. However, they are still considered as Spectral Cards when triggering other effects.
A soul tarot card is a Major Arcana card said to represent a person.
The art of Black Hole appears to be pulling in the sides of the card and its own name tag towards the center by the force of its gravity.
Ghost Deck). It is possible to spawn Spectral Cards via certain Jokers, or, in certain circumstances, purchase them in the shop, in which case they will take up a Consumable slot.
The Soul and 
Black Hole. These two can only be found in Booster Packs, with the Spectral and Arcana packs being able to contain 
Sixth Sense and 
SĆ©ance, or found in the shop when using the 
Familiar, 
