Friend card

Friend cards appear in Kingdom Hearts Chain of Memories as a type of playing card which summons an ally of Sora or Riku to help them during battle. They can be identified by their green borders, which they share with item cards. Friend cards behave identically to the other types of playing card, but unlike the others they cannot be collected, and are instead randomly obtained during battle and disappear when the battle is finished.

As in Kingdom Hearts, these allies generally cannot be used on all worlds. Each friend summon can be upgraded to more powerful levels by stocking multiples of that friend card, though they can also be used in various combinations with other friend cards, as well as attack, magic, summon, and item cards to perform different spells and summons unavailable in the other games. Many of these new combinations are Kingdom Hearts versions of traditional  spells like "Terror" or "Teleport".

Friend cards are available in both Sora's tale and Reverse/Rebirth, but are only used by Sora and Riku.

Gimmick Card
The Gimmick Card, also known as the Trick Card, is a special Friend Card that can be obtained under certain conditions during boss battles. It depicts a green. The card acts as a 0 card, but cannot be broken and will still take effect if used against another 0 card. Using a Gimmick Card will generate effects that can give Sora and Riku the upper hand. In practice it is quite similar to a Reaction Command.
 * Guard Armor: The Guard Armor collapses into a pile and does not attack.
 * Trickmaster: The table and chair reappear in the middle of the arena, allowing the Trickmaster's weaker head and chest to be attacked. In Re:Chain of Memories, Trickmaster is stunned as well.
 * Parasite Cage: The rotating platforms are replaced with one large platform. In Re:Chain of Memories, the stomach acid disappears.
 * Darkside: A broken piece of wood flies in, allowing you to fly up to the Darkside's head for close-range attacks. In Re:Chain of Memories, several pillars of rock form a staircase to the Darkside's head.
 * Jafar: All the floor panels rise to the highest level, allowing Iago to be more easily attacked.
 * Oogie Boogie: The metal wall guarding Oogie Boogie drops into the floor. In Re:Chain of Memories, Oogie Boogie is stunned as well.
 * Ursula: Ursula's tentacles disappear, and she drops her head to the ground. In Re:Chain of Memories, Ursula gags on a sharp intake of water and is stunned as well.
 * Dragon Maleficent: A pile of stone blocks fall from the ceiling, allowing her head to be more easily attacked. Maleficent can break each platform layer when stepping. In Re:Chain of Memories, a floating platform appears that allows the player to reach Maleficent's head while also keeping them out of any flames on the ground.