The creepy set and the costumes were both for my 2017 Halloween Special.  Costumes have infinite durability, but don't have any armor protection.  Some have full set bonuses.  They are mostly for cosmetics.  First off, the Wither King.  A nice wither-themed royal suit, topped with a wither head with a crown.  A full set grants you swiftness.  Ragged clothing is basically... ragged clothing.  There is no hat included in the set.  Lastly is the ghost(face) suit.  A cloak that covers most of you with a creepy mask towards the top, and a full set grants you jump boost.  Time to give your friends a fright!

The 2018 Halloween Update added four new costumes!  The Skeleton Costume, crafted from bones and black wool, give you haste.  The Soul Reaper costume, crafted with Soul Fragments and Black Wool, affects you with Night Vision.  The Scythe that accompanies this set does 5 dmg and is unbreakable.  The Werewolf costume is crafted using Leather, Grey Wool, and Blue Moon Quartz.  It gives you strength.  Finally, the Clown costume gives you absorption and is made from different types of wool.