Passive effect

Many items and equipment sets have passive effects or set effects, which trigger on their own when equipped. These effects confer a wide variety of benefits, both combat and noncombat. In the case of a passive effect that applies to an equipment set, all items of that set must generally be equipped for the set to activate.

According to Jagex, combat-related set effects are only supposed to affect autoattacks and not abilities, but in-game testing has determined that abilities are affected as well.

Barrows equipment
In order for a set effect of Barrows equipment to trigger, all four pieces must be worn: Head, body, legs, and weapons.

Void Knight equipment
A full set of Void Knight equipment, available from Pest Control, grants a passive effect that increases the accuracy and damage of attacks made while wearing it. The set increases damage by 5%, but the accuracy bonus is not known. The combat style that receives the boost is dictated by which helm, between the void melee helm, void ranger helm, and void mage helm, is equipped. A full set of Void Knight equipment consists of the helm along with the void knight top, void knight robe, and void knight gloves. After completion of The Void Stares Back, an elite void knight top and elite void knight robe can be worn instead.

The void knight deflector, a reward from Conquest, allows a player to equip another item in place of the top, bottom, or gloves and still receive the set effect.

Nex Armour
Wearing any piece of Torva, Pernix, or Virtus armour will cause all factions of monsters in the God Wars Dungeon (aside from bosses) to be unaggressive.

Experience-boosting sets
These items grant an experience bonus for a certain skill when worn. For some outfits, such as the golden mining suit, each individual piece grants a bonus, and the listed amount is for the entire set. For other sets, all items must be equipped to receive the bonus.

God Wars Dungeon protection
Many pieces of equipment affiliated with the gods Saradomin, Zamorak, Armadyl, Bandos, and Zaros provide a passive effect that prevents followers of that particular faction from being aggressive within the God Wars Dungeon. This effect does not apply to the bosses or to their bodyguards. In the case of Zarosian items, the protection is applied to all four factions, but it will not protect from Zarosian followers in the Ancient Prison.