Although "Cyber Dragon" equipped with this card while 2 other copies of "Cyber Dragon" and 3 copies of each of the other Cyber Dragons listed above are in the grave would be 100 points stronger for a total ATK of 12000.
On "Harpie Queen" that would make a total of 14500 ATK. This is the highest attack power you can get with this card's effect without additional duplicates of monsters with the same name as the equipped monster in your opponent's Graveyard.
With a standing potential total of fifteen monsters in one deck which may share a name, a Harpie themed deck is statistically the best way to exploit this card's effect. Typically a mere seven-eight copies of "Harpie Lady" are required to empower one copy to OTK.
Equip to "Chain Thrasher" to exploit its card effect. With one "Chain Thrasher" in the Graveyard, its attack becomes 1900, and can attack twice. With two copies of "Chain Thrasher" in the Graveyard, its attack becomes 2800 and it can attack three times.
If you have three copies of each: "Skull Servant", "Wightmare", "Wightprince", "Wightprincess" and "The Lady in Wight" in your deck, this card can give any one of them a potential maximum boost of 12600 ATK; enough for a OTK (provided the other 14 copies are in your graveyard).
This boost doesn't work with "King of the Skull Servants" as his name on the field isn't 'Skull Servant' even though it is part of his name.