Killer sets are really op but are almost imposible to get.
i have a santa set and a good sword which works good for me in pvp, enchants are =
Fast Turn (Weapon) - There is a chance to deal more damage.
Paralyze (Weapon) - gives them slowness.
Thor (Weapon) - There is a chance to strike lighting on your opponents, which deals extra damage.
Vampire (Weapon) - There is a chance to be healed by one heart when attacking.
Rage (Weapon) - More damage to mobs.
Double Damage (Weapon) - Has a chance to deal double damage.
Block (Weapon) - Blocking with a Sword increases your Resistance.
Assassin (Weapon) - There is a chance of inflicting a poison effect on your victim.
Silence (Weapon) - There is a chance to stop the activation of your opponent's custom enchants.
Trap (Weapon) - There is a chance to give a slowness effect to an enemy.
Blessed (Weapon) - There is a chance of removing debuffs.
Confusion (Weapon) - There is a chance of causing the nausea debuff on your opponent.
Viper (Weapon) - There is a chance to give the enemy poison.
Penetrate (Weapon) - Inflicts more damage on your opponent
Devour (Weapon) - Multiplies damage against opponents with active slowness
Blindness (Weapon) - There is a chance of causing the blindness debuff on your opponent.
Execute (Weapon) - Extreme Damage increase when your opponent is at low HP.
Enrage (Weapon) - The lower your HP is, the more damage you deal.
Demon forged(Weapon) - Does more damage to opponents armour.
These are the enchants i got on my sword, The important ones(in my opinion) is demon forged, rage, fast turn, paralyz and other enchants that give slowness and stuff to the enemy.
I dont know if everything i typed is the best or if it is right, check what suits you the best at /enchantments.
My armour enchantments are =
Burn Shield (Armor) - Gives you fire protection.
Voodoo (Armor) - There is a chance to give weakness to the enemy whos hitting you.
Freeze (Armor) - There is a chance to slow enemy whos hitting you.
Quickdraw (Armor) - Decreases the draw time.
Angelic (Armor) - Chance to give a big health boost at low health.
Hardened (Armor) - Armor takes less durability damage
Gears (Boots) - Gives you a speed buff.
Overload (Armor) - Gives you an overload of extra health hearts / Permanent increase in hearts
Drunk - Gives strength
These are the enchants i use and Angelic, hardened, drunk, gears and overload is a big deal, especially hardened. You wont last 3 minutes without hardened