In the digital underground of the Yu-Gi-Oh! Forbidden Memories modding community, (specifically the 15-Card Drop
Disadvantages:
Dragon Treasure: Dropped by Pegasus (BCD) or Isis (BCD) with a 32% drop rate.
If you want to optimize your playtime, focus on these specific opponents: Key Drops (S/A Rank) Meadow Mage Meteor B. Dragon, Dark Magician, Skull Knight Pegasus Megamorph, Dragon Treasure, Bright Castle, Widespread Ruin Seto 2nd Blue-Eyes White Dragon, Zera the Mant, Dragon Treasure Seto 3rd