"This is a fun little mod I put together for a server awhile ago. Craft playing cards in five different suits (diamond, heart, club, spade, joker) for different effects, but beware: they may backfire when used, turning the effect against you! " - (WillDaBeast509, 2014)
The base cards from the mod are created using dye and paper. Those cards do not do anything. When five of these cards are crafted with either bone meal or ender eyes, they become loaded or a "Hoyle" card respectively. A loaded card has a 40% chance of backfire, whereas a "Hoyle" card only has a backfire chance of 10%. Each card has their own unique backfire effect related to their positive effect.
The Cards:

(Left to Right) Diamonds, Hearts, Clubs, Spades, Jesters.
DIAMOND

HEART
CLUB

SPADE
For the sneaky ones. Gives you night vision, speed, and invisibility for 20 seconds. Enough time to sneak into your friend's base or make an escape from attackers. Backfires will give you blindness and slowness for 10 seconds.
No picture because original mod author deemed it unnecessary.
JOKER
The fun one. A thrown card that hits another living thing will cause you to swap places with it. Use your mind, as this can be applied in all sorts of creative ways. Jump off a cliff then throw it at someone, dooming them to fall, or just use it to reach difficult places, etc. If it backfires, it will teleport you to a random location within 50 blocks.


CRAFTING THE CARDS





This mod was originally made for 1.6.4 by a mod creator named WillDaBeast509. Check it out here and here.
I took the icon off of a TheAtlanticCraft thumbnail going over that very mod.