Set Bonuses
These bonuses will likely have the high end of piece requirements, such as requiring 4 or 6 pieces. The smaller piece bonuses will be more passive in nature (stat benefits, etc).
Noxious Cloud - Activating Noxious Knives reduces the cooldown of Toxic Haze by 3 seconds. Every enemy affected by Toxic Haze takes 20% more damage from Noxious Knives.
Debilitator - Debilitate gets two ability charges.
Healing Haze - Toxic Haze heals any allies standing inside it by a small amount.
Tactician - Tactical Advantage gets an additional stack. Having a Tactical Advantage increases your damage and healing by 1%.
Which one of these is meant to be the healer set bonus. Sorcs on the PTS had a set bonus that interacted with Resurgence. None of these interact with the Operatvie healers abilities. The only one that comes close is tactician but its for both heals and dps and doesnt seem like a big gain to have it for 1%