Thx, dear D.A. Member!
Hope not to spoil other's imagination, but I've got some vague ideas about it ... now with your provocation I deffinitelly gotta have some

and I'll try to avoid the cliche ones
DD's
Patronus first (it's easier

):
*maybe not a golden but a silvery Phoenix
*Griffindor's sword (again, not golden but silver

)
*Harry Potter himself

, just like he is
*a wollen sock (for a bigfoot

) (not to steal ideas: I think I've read the sock thing somewhere else, but in connection with house elves ...

)
*joke: Phineas Nigellus wearing a muzzle to shut his serpent's mouth
DD's
Boggart:
*Voldie brandishing Griffindor's sword (sorry for the sword fetish, it's not entirely my fault but in the time of the Founders a sword had a function of nowadays muggle cell phone

)
*joke: Harry staying together with Cho (= hysterical idiot!

)
*Voldie learns to love --> this means Harry's power of love is no longer Harry's advantage, that both have it
*his own death before Voldie is defeated
*joke: DD has to sleep barefoot, b/c he's run out of wollen socks
DD's worse memories:
*first, I don't think they contain Harry's parents death - if so, this means DD was
witnessing their death
*loads of cruelty from the period of Voldie's first rise (sth. like concetration camps, of massive killings)
*maybe another, even more gruesome, prophecy that completes the one from the book 5
*Wizengamot trial when Sirius got his Azkaban sentence --> this one is my fav! In the end of book 5 Harry actually blamed DD for Sirius' death!!!