Most great props have already been mentioned here, so I will go with some lesser mentioned ones.
Ray gun from Mario Bava's Planet of the Vampires. And full spacesuit.
Screen accurate mask from Bava's Black Sunday. And replica paintings too
Anything from Kurosawa's Throne of Blood! Armor, banners, ect..
1:1 devil from Alex de la Iglesia's Day of the Beast
1:1 Templar Knight from the Blind Dead films.
Exact type of hammer from [REC].
Book from the Pang brothers the Eye 10.
And chess set from Berman's Seventh Seal