Power armour sets provide increased damage output rather than health. These sets use invention perks optimised for damage output towards bosses.
Tank armour sets provide increased health and defence, and are used by players in the tank role at bosses.
Slayer sets are power armour sets equipped with slayer specific perks to help speed up tasks.
Shields and Defenders
Shields and defenders are used to cast defensive abilities.
Gloves and Boots
Gloves and boots are used to provide armour and strength boosts depending on the players role. They can not be augmented.
Specialty armour pieces are from achievements and quests and are useful in various specific situations.