Torture Chamber - an occupied rack, jacob's ladder, iron maiden, perhaps impaled bodies on stakes, head/thumb screw chair, brazier/hot coals/tongs... prison cells.
Vivisectionist's Operating Room - a set of 19th century medical tools (as one object), an operating table, body parts, glass jars with specimins (jars of eyeballs, etc.), maybe Frankenstein's monster partially assembled.
A Faustian Wizard's Lab/Study - grimoires, scrolls, lab equipment, still, solomonic circles, magic squares, varying colored miasma - red, pale blue, green, white, a signed Faustian contract, a copy of the Necronomicon.
Aristocratic Mansion Furnishings - suit of armor on display, candelabra, ornate desk with accounting among other activities, dining table and chairs, master's chair, fancy couch.
Dead Garden - polluted fountain, dead roses and other plants, dead trees, broken statues.
Ghostly Effects - a semi-transparent ghost, shadows on floor with no one standing there, a whispy shadowy figure, various miasma clouds in red, white, pale blue and green, glow emanating from woman's corpse in glass coffin, ghostly orbs.
Masque of the Red Death - piles of plague victims, corpses on a great pyre, wagons full of corpses, miasma burning torches.
Window cast light/shadow - stained glass cast light, ornate panes cast light/shadow, wrought iron gate cast shadow, window cast light with figure peering in.
Some Statuary - marble busts, a few statues, ornate tombstones, stone gargoyles, ornate stone gazing pool (with ghostly drowned figure within).
Random Ideas - small flock of bats, perhaps some hanging bats, perhaps a full murder of crows...
If I get enough ideas, I might make this a 100 object set - but I need more ideas (hint, hint...)
Witch Accoutrements - boiling cauldron, black cat, broom, apothecary equipment and drying herbs hanging.