Here's a few cards I made recently when I was bored. Most of them probably suck.
Kozaky's Assistant
2/DARK/Fiend/Effect
When this card is summoned successfully, you may add three cards with "Kozaky" in their name from your deck to your hand.
Song of the Angels
Continious Spell Card
For each monster with "Angel" in it's name, the controller of that monster gains 200 Life Points.
Angel Knight
Light/4 Stars
Attack: 1800
Defence: 1300
Fairy/Normal
A knight who came from the heavens in order to eliminate the Dark World.
Dragon of the Heavens
Light/5 Stars
Attack: 2300
Defence: 1400
Dragon/Effect
This card gains 100 ATK and DEF points for each monster with Angel in it's name on the field. This card also loses 100 ATK and DEF for each monster with Dark World in it's name.
Heavenly Battlefield
Field Spell
All cards with Angel in their name gain 300 ATK points. All cards with Dark World in their name lose 100 ATK points.
Double Damage
Continious Spell Card.
When a spell or trap inflicts damage to a player's life points, double the amount of damage the player would normally receive.
Eradicating Light
Equip Spell Card
This card can only be equipped to a monster that is either LIGHT, Fairy, or contains Angel in it's name. When the equipped monster attacks a Dark World monster, the targeted monster loses 300 ATK and DEF points.
Chain Summoning
Trap Card
Activate this card only as chain link 3 or higher. Both players Special Summon up to 2 monsters from their hand with 4 or less stars. For each monster Special Summoned this way, the controller of that monster loses 500 Life Points.
Different Dimension's Apocalypse
Spell Card
For each card removed from play, the controller of those cards loses 150 LP per card removed from play.
Phantasm of the Night
Dark/4 Stars
Fiend/Effect
ATK: 1500
DEF: 1800
This card's name is treated as "Dark World Ghost." For each Dark World Ghost in the graveyard, this card gains 300 ATK points. If discarded from the hand to the graveyard by a card effect, special summon 3 "Dark World Ghost Tokens" (Dark/Fiend/2 Stars/ATK: 1000/DEF: 1000) in defence mode. These tokens cannot be used for a tribute summon.
Dark World Ghost
Dark/3 Stars
Fiend/Effect
ATK: 1300
DEF: 1500
This card gains 300 attack points whenever a card with Dark World in it's name is destroyed by battle. If discarded from the hand to the graveyard by a card effect, special summon 3 "Dark World Ghost Tokens" (Dark/Fiend/2 Stars/ATK: 1000/DEF: 1000) in defence mode. These tokens cannot be used for a tribute summon.
Anubis, New Ruler of Dark World
Dark/6 Stars
Fiend/Normal
ATK: 2400
DEF: 2000
The Egyptian lord of the dead has found a land known as the Dark World. After arriving there, he claims to be the next ruler of the Dark World.
Dark World Warlock Lv. 3
Dark/3 Stars
Spellcaster/Effect
ATK: 1000
DEF: 1300
For each spell card activated, put one Spell Counter on this card (max 3). For each counter on this card, this card gains 300 ATK. When this card destroys a monster as a result of battle or is destroyed by a card effect, special summon one Dark World Warlock Lv. 4 from your deck.
Dark World Warlock Lv. 4
Dark/4 Stars
Spellcaster/Effect
ATK: 1900
Def: 1300
For each spell card activated, put one Spell Counter on this card (max 3). For each counter on this card, this card gains 200 ATK. By discarding one card from your hand, flip one monster on your opponent's side of the field face-up (flip effects are not activated at this time). When this card destroys a monster as a result of battle or is destroyed by a card effect, tribute one monster on your side of the field to special summon one Dark World Warlock Lv. 6 from your deck.
Dark World Warlock Lv. 6
Dark/6 Stars
Spellcaster/Effect
ATK: 2500
DEF: 1800
This card can only be summoned by the effect of Dark World Warlock Lv. 4. For each spell card activated, put one Spell Counter on this card (max 4). For each counter on this card, this card gains 200 ATK. By discarding one card from your hand, destroy one spell or trap on the field. When this card destroys a monster as a result of battle or is destroyed by a card effect, tribute two monsters on your side of the field to special summon one Dark World Warlock Lv. 9 from your deck.
Dark World Warlock Lv. 9
Dark/9 Stars
Spellcaster/Effect
ATK: 3100
DEF: 2500
Thi card can only be summoned by the effect of Dark World Warlock Lv. 6. For each spell card activated, put one Spell Counter on this card (max 5). For each counter on this card, increase the ATK and DEF of this card by 150 points. Pay 1500 life points to discard both player's hands. Each player then draws 5 cards. This card negates the effect of any monster, spell, or trap that targets it.
Dark World Protection
Quick-Play Spell
This card can only be activated when a monster is targeted by a spell or trap card. Remove 3 counters from a card to negate the activation of the spell or trap card and destroy it. Discard two cards from your hand afterwards.
Dark Tribute
Spell
Special summon one monster with 5 or more stars. Discard from your hand twice the amount of monsters normally required to tribute summon the summoned monster.
Destiny Hero - Sound Warrior
Dark/3 Stars
Warrior/Effect
1200 ATK
500 DEF
When this card and another Destiny Hero is on the field, select one monster. The selected monster cannot attack next turn. This effect can only be activated on your turn.