I know that made-up card lists are rampant on the top 10 list, but I would like to make a top 10 list myself.  My cards are in no particular order and hopefully are not what you'd expect from a top 10 list.
10. Cross Knight  Warrior/Light Lv.4
      1900/1500 A knight that fights for his kingdom, he pierces his foe's defenses with a powerful spear.
*Based on the knights of the Crusades, this guy is what Warriors needed, a monster that has a high attack and no real drawbacks.  He is also good for Chaos, basically the warrior version of the Archfiend Soldier only with Light instead of Dark attributes.
9. Equalizing Spell Continuous Trap
       As long as this card remains in play, your opponent may not have more monsters and more Spells and Traps on his/her side of the field than you during his/her turn.  You may not have more monsters and Spells and Traps on your side of the field than your opponent during your turn.  When this card is activated, destroy all cards on the field.
*If used right, a good duelist can control the field by forcing their opponent to play with no support.  The trick is how to use it.  The fact that it is a trap and clears the board may make this card broken, but the effect can screw a n00b or anyone that doesn't use it right.
8. Mystic Scrying Normal Spell
     When you play this card, discard a card.  Take a card from your deck that was of the same type as the card you discarded, either Monster, Magic or Trap, and put it in your hand. Shuffle your deck afterwards.
*This card can help players find that key piece of their combo for a mere discard, but you have to get the same type of card as the one you discarded.  Although game-breaking if used right, you're not always guarenteed you have the right card to discard at the same time as this one.
7. Dark Magus Elf  Spellcaster/Dark  Lv.7
       2700/2100  When this card is Special Summoned onto the field, you may choose one of the following effects:
-Destroy a monster on your opponent's side of the field.  -Your opponent discards a card.
*Another card worthy of Double Coston( besides DMoC, Dark Magician for magician decks and anyone who uses Red Eyes), this card acts kind of like DMoC except that it has two effects when Special Summoned and neither are as good.  Painful Choice could help you Special Summon it faster, but you can have it used against you and the effects don't work if your opponent has neither creatures nor cards(say after Chaos Emperor Dragon).
6.Legendary Huntress  Warrior/Earth  Lv 4
       1000/1000 When this card is sent to the graveyard from the field, move a Trap card from your deck to your hand and shuffle your deck.
*I figured since you got two monster searchers, why not other searchers.  This one gets a Trap and can set up your defense for the next turn.  Maybe not as good and Witch or Sangan, but I think that it's useable for some people.
5. Mystical Fairy  Fairy/Light Lv.4
       1000/1000 When this card is sent from the field to the graveyard, move a Spell card from your deck to your hand and shuffle your deck afterwards.
*This is a lot more useful than the last one because you don't have to wait to use the card.  This can be really evil if you haven't used Monster Reborn, Pot of Greed, Change of Heart, etc and need to get one of those game-swinging cards.
4. Dark Meltdown Continuous-Spell
       As long as this card is face-up, you may put a Spell Counter on it for each Spell card that is played by you or your opponent.  When this card is destroyed, your opponent must remove cards from the top of his/her deck equal to the number of counters on this card.
*Deck destruction just doesn't have as much power as it used to with NoC being used more.  This card can be powerful if it stays on the field long enough.
3. Malevolent Contract Quickplay-Spell
       You may Special Summon a monster from your deck at the cost of the 500 Lp*the number of stars that monster's level has.
* Although the Lp cost can really hurt, you can pay 3000 Lp to get a Jinzo out really fast if you need to or any monster you really need at the moment.  The Lp cost simply makes the card more feasible in controlling its power.
2. Horn of Armada Summoning   Spell/Normal
       Both players Special Summon up to 5 monsters from the hand or deck.
*Since both players get to use this card's effect, it isn't too cheesy as your opponent may have some powerful stuff in his/her deck.  You can bait out their powerful stuff and just Mirror Force when he/she attacks.
1. Legendary Fortress  Spell/Field
       Increase the attack and defense of all Warrior type monsters by 200 points.  You may play Warrior type monsters from your hand as Special Summons at the cost of 500 Lp per summon this way.
*Great for Warrior Decks, which can use this card to swarm in monsters.  Pull out a Freed the Matchless General or Buster Blader for no tributes for only 500 Lp. 
That's this article.  E-mail me at zeno9d9@aol.com for any responses to this post.