A set bonus is a special type of gear bonus that gives you a boost in battle, like making some of your abilities stronger or making them usable more often. The more pieces of set bonus gear you collect, the more bonuses you will get.
UPDATE 2022: With update 7.0, set bonuses are no longer useful beyond level 75, and level 80 players have a new type of item called Legendary Implants. If you are looking for the cosmetic shells, see this armor guide.
Old video on how it worked:
Set bonuses only exist on the pieces of armor that you can “wear” (at level 75) – Head, Chest, Hands, Legs, Boots, Belt and Bracers. There’s no set bonus on earpieces, implants, relics, weapons or tactical items. Some set bonuses only have a 2-piece set bonus, while others have a 4-piece or 6-piece bonus. You can also mix-and-match multiple set bonuses by having 2 of one set, 2 of another, and 2 of a third, or by have two from one set and four from another. Some set bonuses are restricted to certain classes, but there are also generic set bonuses that can be worn by any class. Set bonuses are easy to notice while you are working on gearing up, because they only appear on items with a gold-border – but not all gold-bordered items are set bonus items,
Your Set Bonus is tied to the shell of piece of gear – not to the armoring, mod or enhancement. If you want to wear a new shell with a set bonus on it but don’t want to lose the look of your current gear, you can create an outfit with your old piece of gear and wear it over your newly-equipped set bonus piece. You do not have to sacrifice fashion to equip a set bonus piece!
Class Set Bonus Lists
Which Set Bonus should you choose?
Old info: When choosing a set bonus for your class to work on earning, you’ll want to first take a look at the list below for your class. you’ll be looking at three different sections in the list – the set bonuses available to your advanced class, the set bonuses available to your class, and the generic set bonuses that can be used by any class. Unlike previous expansions, you’ll have close to twenty set bonuses to choose from. Which one you should choose will depend on a few factors, but the most important are what type of content you like to play, what role you will be playing (tank, dps, healer) and what type of rotation or abilities you want to use. Most players gravitate towards the set bonus sets that are specifically for their class versus the generic sets. Players are still working on the theorycrafting to decide which set bonus is the theoretical best for their class – until more class guides have been created, you can read through the list for your class below and pick one you think will benefit the way you play.
Where can you get Set Bonus pieces?
New info: See Kai Zykken.
Old info: Set Bonus pieces drop from level 75 content and gearboxes earned through many different ways including Flashpoints, Operations, PvP, level 75 Dailies, Weeklies & Heroics, Story Chapters, Crafting and Conquest. Each set is most commonly dropped through a certain type of content, for example some sets are exclusively found through crafting or from the new Dxun Operation.