PCY/K = The PC Power Of Chaos games. Y/K mean, respectively, Yugi the Destiny, and Kaiba the Revenge. There's a third game, Joey the Passion (PCJ).
Each game had a set of promo cards.
PCY: Had reprints of Dark Magician and Kuriboh, along with Thousand Knives, Windstorm of Etaqua, and Anti-Spell Fragrance.
PCK: Reprint of (what else) BEWD, as well as Aqua Chorus and Seal of the Ancients.
PCJ: Reprint of REBD, along with Sword of Dragon's Soul and Sebek's Blessing.
PCY-001
Windstorm of Etaqua
Trap
Change the battle positions of all face-up monsters on your opponent's side of the field.
PCY-002
Anti-Spell Fragrance
Continuous Trap
As long as this card remains face-up on the field, both players must first set Spell Cards when they use them and cannot activate them until their next turn.
PCY-003
Thousand Knives
Normal Magic
You can only activate this card when you have a face-up "Dark Magician" on your side of the field. Destroy 1 monster on your opponent's side of the field.
PCY-004
Dark Magician
DARK/Spellcaster/7/2500/2100
PCY-005
Kuriboh
DARK/Fiend/1/300/200
Discard this card from your hand to make the Battle Damage inflicted to your Life Points by 1 of your opponent's monsters 0. This effect can only be activated during your opponent's Battle Phase.
PCK-001
Blue Eyes White Dragon
LIGHT/Dragon/8/3000/2500
PCK-002
Aqua Chorus
Continuous Trap
If there are monsters with the same name on the field, increase the ATK and DEF of all of those monsters with the same name by 500 points.
PCK-003
Seal of the Ancients
Normal Magic
Pay 1000 Life Points. Pick up and see all face-down cards on your opponent's side of the field, then return them to their original positions. (The effects of the face-down cards are not activated.)
PCJ-001
Red-Eyes Black Dragon
DARK/Dragon/7/2400/2000
PCJ-002
Sebek's Blessing
Quick-Play Magic
You can only activate this card when a monster attacks your opponent's Life Points directly. Increase your Life Points by an amount equal to the Battle Damage that the monster inflicted to your opponent's Life Points.
PCJ-003
Sword of Dragon's Soul
Equip Magic
This card can only be equipped to a Warrior-Type monster. A monster equipped with this card increases its ATK by 700 points. A Dragon-Type monster that battles with the monster equipped with this card is destroyed at the end of the Battle Phase. (Damage Calculation is applied normally.)