Except for vanities all items are dropped from Halloween bosses.

INT SET
Grim's Hood of Death
Grim's Cloak of Death
Reaper's Scythe of Death (2H)
Reaper's Glow Shield of Death
Grim's Magical Aura of Death (1H)

The set will look like grim reaper
Buy Grim's Wings Vanity to get a crit bonus to your existing set bonus. Set has to be worn for this to work.

STR SET
Devious Plate Helm of Might
Devious Plate Mail of Might
Devil's Great sword of Might (2H)
Devil's Pitchfork of Might (1H)
Devious Skull of Might

The set will look like a devil
Buy Devil's Tail Vanity to get a dodge bonus to your existing set bonus. Set has to be worn for this to work.

DEX SET
Blinding Bat Helm
Blinding Bat Armour
Bat's Shattering Crossbow (2H)
Bat's Lightning Talon (1H)
Blinding Bat's Wing

The set will look like a bat
Buy Bat Teeth Vanity to get a Hit bonus to your existing set bonus. Set has to be worn for this to work.

Also, Halloween rings to be added in the sets?