Curlys Halloween
Really cheesy. but good! anim gifs
http://homepage.ntlworld.com/curly.johnson/halloween.htm
Caverns of Blood
More weird anim gifs - ooooh the cheese!
http://www.cavernsofblood.com/scarystuff.html
Chaos Designs
Halloween features and links
http://www.chaosdesigns.net/halloween/freegraphics.html
Vintage Holiday Halloween
Small sizes but some loverly old fashioned style greeting cards depciting halloween
http://vintageholidaycrafts.com/category/halloween/