Free Icon Sets
5 Halloween Icons: A small collection of nicely detailed icons, but considering the inclusion of some copyright characters, one assumes it is best for personal use only.
8 Horror Icons: A nice collection of 8 horror-themed icons that feature lots of blood and gore.
14 Halloween Vectors: A collection of 14 free pieces of vector art in .PNG and up to 512×512. They come in source files of .AI (CS3) and .EPS.
Benjigarner Halloween Icon Pack: Four .PNG Halloween icons that measure 256×256.
CSS Creme Halloween Icons: A free set of 11 Halloween-themed icons for you to download.
Danilux Spooky Halloween Icons: These 16×16 icons are perfect to replace the icons on your computer.
Deleket Halloween Avatars: A fun collection of 20 Halloween avatar faces of various monsters and ghouls.
Design Bliss Halloween: Four Halloween vector images for RSS icons.
Hybridworks Haunted Hotel: A small, but quality collection of jack-o-lantern icons, a haunted hotel and a hard drive made to look like a tombstone.
IconArchive set of 19 Halloween Icons: 19 various Halloween icons in .ICO and .PNG format, available in 128×128 and 48×48 sizes.
IconDrawer Halloween Pair: Only two icons in this set, but they are very slick and professional looking.
Nonamd Computer Icons: A hefty collection of 42 Halloween-inspired computer icons that all measure 128×128 in .PNG format.
TNerd Social Halloween Icons: A terrific set of social media icons that have been made over for All Hallow’s Eve.
Trick or Treat: A fun collection of four icons related to Trick or Treating.
Vector RSS Icons: A set of three vector RSS graphics with a Halloween theme to them.
Witchery Icons: 11 various witch-themed icons in .ICO and .PNG format, available in 128×128 and 48×48 sizes.
World of Aqua: After Dark: A collection of spooky icons from Iconfactory.
Premium Icon Sets
FastIcon Halloween Emoticons: A set of five pumpkin icons in .ICO, MAC ICONS and .PNG formats, in 16×16, 24×24, 32×32, 48×48, 64×64, 128×128 sizes.
Vista Style Halloween Pumpkin Emoticons: 25 assorted icons in .ICO and .PNG format in 16×16, 24×24, 32×32, 48×48, 64×64, 128×128, 256×256 sizes.
Source Link: http://www.sitepoint.com/spooky-icon-sets-for-halloween/