Butterfly Dagger - Elma OTK

The Butterfly Dagger - Elma OTK varies a bit between the player, but generally revolves around these cards:


 * Butterfly Dagger - Elma
 * Gearfried the Iron Knight
 * Royal Magical Library
 * Exodia the Forbidden One and his limbs

Get Gearfried the Iron Knight and Royal Magical Library face-up on the field, then equip Gearfried with Butterfly Dagger - Elma. Royal Magical Library gains a counter and Butterfly Dagger - Elma is sent to the graveyard due to Gearfried's effect, which is immediately sent back to your hand. You repeat this process while drawing a card every 3 times thanks to Royal Magical Library's effect. Theoretically, you can draw your entire deck, along with Exodia, and win the duel.