Beautiful Chess set: A beautiful set of “ivory” chess pieces, actually carved from human bone.
The bedspread of nightmares: If someone sleeps beneath it they will have nightmares, initially quite mild but which get worse the more nights they sleep under the bedspread.
The Pictureframe of Souls: Any portrait in this frame will change, bit by bit, over the course of a week to reveal the current state of the souls of anyone in it. The cultist used it to find True Innocents to sacrifice.
Butterknife of paralysis: Doesn’t do any more damage than a regular butterknife, but someone being cut with this can’t do anything but watch you saw into them very slowly. This is from a wish made to a demon long agon. The wisher is long dead, dammed to hell, the butterknife is still here.
The Locket: Beautifully made from shining gold, this locket would be a perfect gift for the wife, girlfriend, mother or daughter of a nobleman, but for one hitch: It’s welded shut.
Essentially, a really nasty demon is bound in the locket, to give strength to the cultist. If the locket is ever actually opened, boom, he comes out and tries to kill everything. He wants revenge. Perfect thing for a PC to give a love interest…