MITSURO ITACHU'S DECK:

Assault Ship (x3)
Stars: 4
Attribute: Light
Type: Machine
Attack: 1500
Defense: 1200
"FLIP: Special Summon 2 Assault Tokens (2/1000/1000)."

Destroyer Class – USS Guardian
Stars: 6
Attribute: Water
Type: Machine
Attack: 2400
Def: 2500
"This card may be Normal Summoned without Tributes. If you do, its original ATK and DEF are halved. If you pay 1000 Life Points, this card can attack directly during this turn."

Destroyer Class – USS Liberty
Stars: 5
Attribute: Water
Type: Machine
Attack: 2000
Def: 2300
"When this card is summoned, negate the effects of Spell and Trap Cards until your opponent's second End Phase."

Destroyer Class – USS Defender
Stars: 5
Attribute: Water
Type: Machine Attack: 2400
Def: 2400
"This card cannot be destroyed in battle by monsters with more than 3000 points."

Patrol Boat (x2)
Stars: 3
Attribute: Light
Type: Machine
Attack: 1400
Def: 1300
"FLIP: Look at all facedown cards on the field, then return them to their original positions."

Aircraft Carrier
Stars: 6
Attribute: Water
Type: Machine
Attack: 1500
Def: 1800
"Once per turn, you can look at your opponent's hand."

Submarine-Ohio class
Stars: 4
Attribute: Light
Type: Machine
Attack: 1400
Def: 1200
"When this card is selected as an attack target, inflict damage to your opponent equal to this card's current ATK."

Tanker Ship (x3)
Stars: 2
Attribute: Dark
Type: Machine
Attack: 0
Def: 1400
"Flip: Special Summon 2 Tanker Tokens (1/500/500)."

Helicopter Support Squad (x2)
Stars: 4
Attribute: Light
Type: Machine
Attack: 1300
Def: 1200
"When the opponent selects a monster on your side of the field as the target of an attack or an effect, you may change the target to this card."

Light Assault Ship (x2)
Stars: 3
Attribute: Water
Type: Machine
Attack: 1300
Def: 1600
"Negate the effect of Trap Cards that destroy a monster(s) on the field."

Heavy Assault Ship (x2)
Stars: 4
Attribute: Light
Type: Machine
Attack: 1400
Def: 1500
"When this facedown card is attacked, it becomes a Continuous Spell and the attack is negated. During the second End Phase after this effect is activated, destroy this card and the monster with the highest attack points on the field."
Navy Hospital Ship (x3)
Stars: 4
Attribute: Light
Type: Machine
Attack: 500
Def: 2000 "Once per turn, increase your Life Points by 500 for each 'Navy Hospital Ship' in the Graveyard."

USS Liberation
Stars: 10
Attribute: Water
Type: Machine/Fusion
Attack: 3500
Def: 3400
1 "Destroyer Class" monster + 1 "Destroyer Class" monster + 1 "Destroyer Class" monster "This card can only be Special Summoned by removing from play the fusion material monsters. This card cannot be destroyed by Trap Cards. Once per turn, when this card would be destroyed by battle, it is not. When you declare an attack with this card, Tribute 1 monster on your side of the field to turn it into a direct attack."

Upgrade
Equip Spell Card
"Equip this to a 'Destroyer Class' monster. Increase the monster's ATK by 500. Send this face-up card from the field to the Graveyard to destroy 1 card on your opponent's field."

Salvage Yard
Spell Card
"Return one monster from your Graveyard to the top of the Deck."

Coastal Defense
Quick-Play Spell
"Negate the effects of all Spell and Trap Cards for one turn. The ATK and DEF of all face-up monsters become equal to the highest original ATK on the field until the End Phase of this turn."

Naval Assault
Trap Card
"Negate the activation of a Spell Card and destroy it."

Naval Protocol
Spell Card
"Destroy a face-up Spell Card."

Resupply
Spell Card
"Both players draw cards from their Decks until they have five cards in their respective hands."

Reinforcement Forces
Trap Card
"Activate only if you have 1 or more Tokens on the field. Special Summon 2 Tokens of the same name."

Light on the Horizon!
Field Spell Card
"Increase the ATK and DEF of all Light-attribute monsters by 500 points."

Hyper Cannon Blast!
Equip Spell Card
"This card can only be equipped to 'USS Liberation'. The ATK and DEF of the equipped card become 4500."

Liberation
Trap Card
"Pay 1000 Life Points. Special Summon 1 Level 5 or lower monster from the opponent's Graveyard to your side of the field."

Amphibious Landing
Spell Card
"Special Summon up to 3 cards with 'Assault Ship' in their names from your Graveyard in defense mode. The summoned cards cannot attack or change their battle positions."

Open the Gateway
Spell Card
"Both players unite their Graveyards with their Decks and shuffle them. Then both players draw three cards from their shuffled Decks."

Lock on!
Continuous Spell Card
"Either player may choose to declare 1 direct attack per turn. Other monsters may not attack during the same turn this card's effect is activated."

Defensive Covering Fire
Continuous Spell Card
"This card remains face-up for 3 of your opponent's turns. No monsters can attack. Destroy this card during your opponent's third End Phase after this card was activated."

Trivia:
The above cards are courtesy of Titanic X.

GHOST DUELIST CARDS:

Eschatos
Stars: 10
Attribute: Divine
Type: Divine-Beast
ATK: 2000
DEF: 1800
"Once per turn during your Battle Phase, you can equip this card to a face-up monster your opponent controls, OR unequip it to Special Summon this card in face-up Attack Position. The equipped monster loses ATK equal to this card's original ATK. If this card destroys an opponent's monster by battle, it gains the destroyed monster's effects."

Ultimate Destiny
Spell Card
"Activate this card only if you control a face-up Eschatos. Special Summon 1 Grail Token (Divine-Fairy-10/2000/1800) in face-up attack position. Your opponent cannot target Eschatos as long as you have a Grail Token on the field. Grail Token has the same effect as your face-up Eschatos."

Lifting the Veil
Trap Card
"Activate this card only if you control a face-up Eschatos. Once per turn, take 1 Veiled Monster card from your deck and equip it to Eschatos."

Divine Tempest
Spell Card
"Activate only if you control a Level 10 or higher monster. Destroy all Spell Cards on the field and inflict 300 points of damage to your opponent for each card destroyed in this way."

Divine Manifestation
Spell Card
"Pay half your Life Points. Special Summon 1 Level 10 or higher Divine-Beast-type monster from your deck. This monster cannot be Tributed or destroyed and returns to the Deck during the End Phase of this turn."

Phantom Battle
Continuous Trap Card
"Pay 800 Life Points during each of your Standby Phases. If you do not, destroy this card. If a face-up 'Eschatos' you control is removed from the field while equipped to another monster, Special Summon 'Eschatos' in face-up attack position. Eschatos gains the effect of the monster it was equipped to when it was destroyed."

Trivia:
The first card I created because I thought Bakura was an awesome villain and wanted one of my own.
The last three cards were contributed by tiramisu19.

ALCHEMY CARDS:

Transmutation Circle – Ouroboros
Continuous Spell Card
"This card cannot be destroyed by card effects. You may pay Life Points in sets of 100 to reduce the ATK of an attacking monster by the same amount paid."

Transmutation Circle – Nigredo
Continuous Spell Card
"This card cannot be destroyed by card effects. During the End Phase of your opponent's turn, destroy any monsters that battled this turn and inflict damage to the card's controller equal to the monster's ATK."

Transmutation Circle – Albedo
Continuous Spell Card
"This card cannot be destroyed by card effects. During the End Phase of your opponent's turn, Special Summon 1 monster that was sent to the Graveyard this turn."

Transmutation Circle – Citrinitas
Continuous Spell Card
"This card cannot be destroyed by card effects. The activation of Trap Cards on your side of the field cannot be negated. You can activate Trap Cards during the same turn they are Set."

Transmutation Circle – Rubedo
Continuous Spell Card
"This card cannot be destroyed by card effects. You may draw one additional card during your Main Phase."

Philosopher's Stone
Spell Card
"If this card exists in your Graveyard during your Standby Phase, you can move it to your hand. After the third activation of this effect, remove this card from play. Once per turn, you may select 1 card from your deck and move it to your hand."

Chrysopoeia
Spell Card
"If this card exists in your Graveyard during your Standby Phase, you can move it to your hand. After the third activation of this effect, remove this card from play. Select one monster on the field. Declare the name of one card and send that card to the Graveyard from your or your opponent's deck or hand. Change the name, type, and attribute of the selected monster to that of the discarded monster."

Elixir of Life
Spell Card
"Select 1 monster. During your third Standby Phase after this card's activation, remove this card and the selected monster from play. The selected monster on your side of the field cannot be destroyed and you take zero Battle Damage from battles involving that monster."

Trivia:
The four stages of the alchemical opus are Nigredo, Albedo, Citrinitas, and Rubedo. Carl Jung also used the same terms to describe stages of psychological development (specifically individuation).
Philosopher's Stone is based almost entirely on the card of a similar name from the GX anime.
Chrysopoeia is the process of transmuting some material into gold.
Elixir of Life and Chrysopoeia are both purported properties or effects of the Philosopher's Stone.

OSCAR APPLE'S DECK:

Twelve Commanders – Aries
Stars: 4
Attribute: Fire
Type: Warrior/Effect
Attack: 1800
Defense: 1000
"This card can attack once during your Battle Phase for each Spell or Trap on your field. If there is a face-up Wind monster on the field, increase this card's ATK by 600 points."

Twelve Commanders – Taurus
Stars: 3
Attribute: Earth
Type: Warrior/Effect
Attack: 0
Defense: 2200
"This card cannot be put in attack position. Your opponent must attack this card. If there is a face-up Water monster on the field, this card cannot be destroyed in battle."

Twelve Commanders – Gemini
Stars: 1
Attribute: Wind
Type: Warrior/Effect
Attack: 200
Defense: 400
"When this card is summoned, you can select 1 face-up monster on your opponent's field and summon a Gemini Token with the same stats and effect. A Gemini Token cannot declare attack. If there is a face-up Fire monster on the field, you may activate this effect once per turn during your Main Phase."

Twelve Commanders – Cancer
Stars: 7
Attribute: Water
Type: Warrior/Effect
Attack: 2100
Defense: 2000
"When this card is summoned by the effect of Seven Demons – Moon, you may Special Summon as many monsters with the name Twelve Commanders from your hand as possible. If there is a face-up Earth monster on the field, once per turn you may move a monster with the name Twelve Commanders from your deck or Graveyard to your hand."

Twelve Commanders – Leo
Stars: 8
Attribute: Fire
Type: Warrior/Effect
Attack: 2400
Defense: 1800
"When this card is summoned by the effect of Seven Demons – Sol, you may Special Summon up to 3 monsters with the name Twelve Commanders from your Graveyard. If there is a face-up Wind monster on the field, once per turn you may Special Summon one monster with the name Twelve Commanders from your Deck."

Twelve Commanders – Virgo
Stars: 2
Attribute: Earth
Type: Warrior/Effect
Attack: 500
Defense: 500
"This card cannot be affected by Spell or Trap cards. If there is a face-up Water monster on the field, all monsters on your field are unaffected by Spell or Trap cards."

Twelve Commanders – Libra
Stars: 1
Attribute: Wind
Type: Warrior/Effect
Attack: 300
Defense: 100
"When you have another monster on your field, this card cannot be targeted by Spell or Trap cards, or by attack from your opponent's monsters. This card can attack your opponent's Life Points directly. If there is a face-up Fire monster on the field, increase Battle Damage inflicted by this card by 300 points."

Twelve Commanders – Scorpio
Stars: 4
Attribute: Water
Type: Warrior/Effect
Attack: 2000
Defense: 0
"This card cannot attack. You can increase the ATK of other monsters on your field by an amount equal to this card's current ATK. If there is a face-up Earth monster on the field, increase the ATK of this card by 1000 points."

Twelve Commanders – Sagittarius
Stars: 3
Attribute: Fire
Type: Warrior/Effect
Attack: 1700
Defense: 1800
"Once per turn, you may choose one of the following effects: Increase your Life Points by 600 for each monster on your field Increase the ATK of this card by the difference between your Life Points and your opponent's Life Points. If there is a face-up Wind monster on the field, double this card's effect."

Twelve Commanders – Capricorn
Stars: 2
Attribute: Earth
Type: Warrior/Effect
Attack: 800
Defense: 500
"As long as this card is face-up on the field, your opponent can only activate Spell and Trap cards that have been set for one turn. If there is a face-up Water monster on the field, your opponent can only activate 1 set card per turn."

Twelve Commanders – Aquarius
Stars: 4
Attribute: Wind
Type: Warrior/Effect
Attack: 1400
Defense: 1600
"When this card is summoned, you can select 1 face-up monster on your opponent's field and take control of it until your End Phase. The monster you control cannot be Tributed for any reason. If there is a face-up Fire monster on the field, you may activate this effect once per turn during your Main Phase."

Twelve Commanders – Pisces
Stars: 2
Attribute: Water
Type: Warrior/Effect
Attack: 700
Defense: 800
"By sending this face-up card to the Graveyard, you can negate an attack by your opponent and end his or her Battle Phase. If there is a face-up Earth monster on the field, once per turn you can negate the activation of a Spell or Trap card that would destroy a monster on your field with the name Twelve Commanders."

Zurvan—The Time
Stars: 10
Attribute: Light
Type: Warrior/Effect
Attack: ?
Defense: ?
1 FIRE monster + 1 WATER monster + 1 EARTH monster + 1 WIND monster
"This card cannot be summoned except by Fusion Summon. This card's attribute is also treated as FIRE, WATER, WIND, and EARTH. As long as this card remains on the field, you must skip your Draw Phase and you cannot summon another monster. The ATK and DEF of this card are equal to the cumulative ATK and DEF of the monsters used in the fusion. When this card attacks a monster in defense mode, inflict Battle Damage equal to half the difference between this monster's ATK and the defending monster's DEF."

Zurvan—The Fate
Stars: 10
Attribute: Light
Type: Warrior/Effect
Attack: ?
Defense: ?
"This card can only be summoned by the effect of 'The God of Death.' This monster's ATK and DEF are equal to 600 times the number of monsters in your Graveyard with the name Twelve Commanders. As long as this card is face-up on the field, destroy all cards that do not have 'Zurvan' in the name and are not named 'Infinite Wisdom,' 'Infinite Power,' or 'Infinite Space.'"

Zurvan—The Absolute
Stars: 12
Attribute: Light
Type: Fusion/Warrior/Effect
Attack: ?
Defense: ?
Zurvan—The Time + Zurvan—The Fate
"The ATK and DEF of this card are equal to the combined ATK and DEF of 1 face-up Zurvan—The Time and 1 face-up Zurvan—The Fate when they were destroyed. This card is unaffected by Spell, Trap, or Monster effects. This card may attack once for each monster on your opponent's field. When this card destroys a monster as a result of battle, inflict 800 points of damage to your opponent's Life Points. If an attack by this card fails to destroy a monster, remove that monster from play until your opponent's 2nd Standby Phase and inflict damage to your opponent equal to that monster's ATK."

Seven Demons – Mars
Spell Card
"All your monsters must attack during your Battle Phase. This card's effect cannot be negated by any other effects."

Seven Demons – Venus
Spell Card
"You and your opponent gain 1000 Life Points. Increase your Life Points by an additional 1000 points for each face-up Twelve Commanders monster on your field."

Seven Demons – Mercury
Trap Card
"Special Summon 1 Twelve Commanders from your Graveyard. Destroy that monster during the End Phase of the turn it was summoned."

Seven Demons – Moon
Spell Card
"Pay 1000 Life Points. Special Summon 1 Twelve Commanders – Cancer from your hand, deck, or Graveyard."

Seven Demons – Sol
Continuous Spell
"Pay 500 Life Points during your Standby Phase in order to Special Summon one Twelve Commanders monster during your End Phase."

Seven Demons – Jupiter
Counter Trap Card
"If you have a face-up Twelve Commanders – Sagittarius or Twelve Commanders – Pisces, negate the activation of a Spell or Trap card or the summoning of a monster controlled by your opponent and destroy the card."

Seven Demons – Saturn
Continuous Trap Card
"As long as this card remains face-up on the field, you may Special Summon 1 Twelve Commanders monster from your Graveyard that was destroyed as a result of battle during this turn. When the summoned monster is destroyed, destroy this card."

Infinite Space
Field Spell Card
"This card's controller may summon monsters in the Spell/Trap Zone."

Infinite Wisdom
Continuous Spell Card
"As long as this card remains on the field, your opponent must show his or her hand. Once per turn, you may pay 1000 Life Points to discard a card from his or her hand."

Infinite Power
Continuous Trap Card
"As long as this card remains on the field, all monsters on your side of the field cannot be destroyed as a result of battle."

The God of Death
Spell Card
"You can only activate this card if you have a Fire, Water, Wind, and Earth monster in your Graveyard. Special Summon 1 Zurvan—The Fate from your Extra deck."

The God of Resurrection
Spell Card
"If 'Zurvan—The Time' and 'Zurvan—The Fate' are destroyed simultaneously, you may move this card from your deck to your hand. If you do, skip your next Draw Phase. Send 'Infinite Time,' 'Infinite Space,' and 'Infinite Wisdom' from your field to the Graveyard to Fusion Summon 'Zurvan—The Absolute.'"

Trivia:
Zurvan is the second monster I created based on Zoroastrianism (Spenta Mainyu from the "Duel Academy" arc was the first). The faith itself has nothing to do with the story; I simply borrowed names and associations. I read about Zoroastrianism during my studies and thought it sounded interesting.
Most of the cards are named for astrological signs. Others are named for the solar planets, which alchemists believed controlled certain elements.