Dark Magic Items
Dark Magic items are magical artifacts that contain sinister, dangerous magical powers. Some, like the Hand of Glory, simply give light, but are obviously created using evil magic; a Hand of Glory actually uses a real human hand, for example. Other Dark Magic items are cursed, like the opal necklace in Borgin and Burkes. Horcruxes are in a category of their own (see).
Borgin & Burkes of Knockturn Alley sells quite a variety of Dark Arts magic items. They include:
cards, a pack of blood-stained (CS4)
hangman's rope, long coil of (CS4)
instruments (rusty, spiked) (CS4)
masks (evil-looking) (CS4)
opal necklace, ornate and cursed
a large black Vanishing Cabinet
Other Dark Magic items available in Knockturn Alley include:
shrunken heads (CS4)
live gigantic black spiders (CS4)
human fingernails (CS4)
number twelve, Grimmauld Place
The glass cabinets of the drawing room of this strange old house contained many items that seemed reluctant to leave their shelves. It is not known if these items were actually filled with Dark Magic or not, but some certainly seemed intent on causing harm. Other sinister items and objects were found throughout the house.
an ornate crystal bottle with a large opal set into the stopper, full of what looked like blood (OP6)
boxes, made of tarnished silver and inscribed with languages Harry did not understand (OP6)
dusty box containing an Order of Merlin First Class given to Sirius' grandfather for Services to the Ministry. Kreacher stole this back, but it was then stolen from him by Mundungus Fletcher after Sirius' death (DH10).
china with the Black crest and motto (evidently the same motto as that on the genealogical tapestry, which means "Always Pure" in French) (OP6)
daggers, rusty (OP6)
a grandfather clock that shot heavy bolts at passers-by (OP6)
a spidery instrument, rather like a many-legged tweezers, which scurried away and tried to puncture Harry's skin (OP6)
a music box that played a faintly sinister, tinkling tune when wound that nearly knocked everyone out (OP6) Kreacher stole this back, but it was then stolen from him by Mundungus Fletcher after Sirius' death (DH10).
a ring, large and golden, bearing the Black family crest (OP6)
an ancient set of purple robes that tried to strangle Ron when they were removed from their wardrobe (OP6)
several ancient seals (OP6)
snakeskin, coiled (OP6)