You allow Jester to examine your Seven of Hands.
Jester tells you, "Oh goody, you found one. Come back when you have the whole deck."
The cards are givable/tradable. Repeat cards can also be exchanged by giving a Jester's Token to a Casino owner then giving the repeat to the High Stakes NPC, who will give you a random card in return.
Part of the Jester's Cards quest, the cards that make up the Deck of Hands are:
Combine the cards in order, from Ace to King:
Besides the cards of hands, there is also a jester card. This acts as a "joker", so can be used for every missing card in the deck.
Verified to drop off the following creatures:
See also Deck of Eyes.