I ship Nagini/Gryf-Sword.
Nagini and the Gryffindor Sword had a brief, sensual whirlwind christmas vacation romance (during Harry's second year) up until the Sword was pulled away by Harry in his hour of need against the Basilisk. But the Sword wasn't careful in this strange snake that it found itself thrusting into. And shortly thereafter, the Basilisk died. The Sword was wracked with guilt and remorse that not only had it caused the death of a relative of Nagini's line, but also that it had inadvertently cheated on it's lady-love (albeit at Harry's insistence - meddlesome boy!).
The years passed and the Gryffindor Sword kept itself apart from the it's magical artifact peers, locked in a glass trophy case in the Headmaster's office, never knowing yet always wondering what it's lady-love was up to.
When the Hogwarts Battle came, Nagini yearned to enter the castle proper and find her true love, but she had to obey her Master.
When the Sword was called upon by the 'Hero' Neville Longbottom, it could not believe it - there was it's lady-love. And in their desperation to be with each other again, they threw caution to the wind, and in that fateful moment, the Sword kissed it's lady-love and took it's next victim in that heartbeat.
Now? Now the Sword sits gathering dust, allowing nobody near to buff, shine and polish it. Allows nobody to clean off the stain of all that is left of it's lady-love. None come near but for the Sorting Hat and the last suit of armour, to drink to fallen friends, comrades, suits...and lost lady-loves.