The Hexblade (5e Equipment)
From D&D Wiki
Weapon (Longsword), Legendary (requires attunement and be a hexblade)
Shared pact: get one extra spell slot up to 4th level(held by the hexblade weapon)
True pact weapon: circumvents the pact of blade feature, treating it as a magic weapon. Also it is effected by the weapon change feature to be any weapon the wielder chooses
Double hex: the hexblade adds an additional hexblade's curse to be used on another character
Joyous boons: every boon of the patron deity except the 1st(6th, 10th, 14th) adds a +1 to magic attack and damage rolls.