The "Bride of Frankenstein" inspired lab set is Posenstein here at
http://www.renderosity.com/mod/bcs/index.php?ViewProduct=18426&

Don't forget Andi3D's free bone and horror props. Most of his commercial stuff is on sale for $5.
http://www.andi3d.co.uk/

Although Sixus1 has been mentioned, Jef only talked about a new character while there are dozens of fully textured monsters going for $5 at their site.
https://www.sixus1media.com/catalog//

The DAZ PC has had Halloween themes in the past resulting in some of these classics:
Witch Hazel http://www.daz3d.com/i.x/shop/itemdetails/-/?item=1614
Stonemason's Graveyard http://www.daz3d.com/i.x/shop/itemdetails/-/?item=2717

My visual indexes of Poser content are at http://www.sharecg.com/pf/rgagnon