Armor set

= Class Sets = Every class (excluding Death Knights, who do not have a dungeon set) has "dungeon", "raid" and "PvP" equipment sets available to them. These sets are typically head, shoulder, chest, wrist, hands, waist, legs, and feet items (8 pieces altogether), but set composition can vary dramatically.

Theoretically, these sets benefit the activity one engages in to acquire them: PvP sets are best in PvP situations, raid sets in raid situations, etc., but some players have found it more beneficial to mix and match.

All sets give extra bonuses when wearing multiple pieces of the set.

PvP Gear Sets

 * Level 60 Low Tier Set - Sold from the faction PvP vendors in Stormwind and Orgrimmar.
 * Level 60 High Tier Set - Sold from the faction PvP vendors in Stormwind and Orgrimmar.

Dungeon Sets

 * Dungeon Set 1 - Prior to patch 4.0.3a this was dropped in Stratholme, Scholomance, Upper, and Lower Blackrock Spire. This set is no longer obtainable.
 * Dungeon Set 2 - Prior to patch 4.0.3a this was obtained through a long quest chain, where you would upgrade the dungeon 1 set. This set is no longer obtainable.

Raid Tier Sets

 * Tier 1 - Dropped from bosses and trash in Molten Core.
 * Zandalar Tribe - Prior to patch 4.0.3a this set was dropped in Zul'Gurub. This set is no longer obtainable.
 * Tier 2 - Dropped from all bosses within Blackwing Lair. One piece (the legs) is dropped from the final boss of Molten Core.
 * Cenarion Circle - Dropped from select bosses within the Ruins of Ahn'Qiraj.
 * Tier 2.5 - Dropped from select bosses within the Temple of Ahn'Qiraj.
 * Tier 3 - Prior to patch 3.0.2 this set was dropped from various bosses within the original Naxxramas instance. This set is no longer obtainable.

PvP Gear Sets

 * Battlegear - Sold by Keepers of Time, Lower City, Sha'tar, Thrallmar/Honor Hold and the Cenarion Expedition factions upon reaching reputation.
 * Season 1 - All weapons and off-set armor no longer available. On-set armor purchased from Karynna on the Isle of Quel'Danas for Tier 4 tokens.
 * Season 2 - All weapons and off-set armor no longer available. On-set armor purchased from Olus and Soryn on the Isle of Quel'Danas for Tier 5 and 6 tokens.
 * Season 3 - All items (excluding rings) were removed.
 * Season 4 - Bought with honor from in Area 52 in Netherstorm.

Dungeon Sets

 * Dungeon Set 3 - Dropped from Shattered Halls, The Steamvault, Sethekk Halls, Shadow Labyrinth, Botanica, Mechanar, Arcatraz, and Black Morass.

Raid Tier Sets

 * Tier 4 - Dropped from Karazhan, Gruul's Lair and Magtheridon's Lair.
 * Tier 5 - Dropped from Serpentshrine Cavern and Tempest Keep (The Eye).
 * Tier 6 - Dropped from Hyjal Summit, Black Temple and Sunwell Plateau.

PvP Gear Sets

 * Season 5 - No longer bought with honor. Purchased from various vendors in Dalaran with Justice Points. Hands/Legs/Chest are also dropped from 10/25 man Archavon the Stone Watcher and 10 man Emalon the Storm Watcher.
 * Season 6 - Purchased from various vendors in Dalaran and the Argent Tournament Grounds for Justice Points. Most pieces are also dropped from 25 man Emalon the Storm Watcher and 10 man Koralon the Flame Watcher.
 * Season 7 - Purchased from Arena vendors in the Dalaran Sewers and faction PvP vendors in Stormwind and Orgrimmar. Most pieces are also dropped from 25 man Koralon the Flame Watcher and 10 man Toravon the Ice Watcher.
 * Season 8 - Purchased from Arena vendors in the Dalaran Sewers and faction PvP vendors in Stormwind and Orgrimmar. Most pieces are also dropped from 25 man Toravon the Ice Watcher.

Dungeon Sets
There were no new dungeon sets released with Wrath of the Lich King.

Raid Tier Sets

 * Tier 7 - This set has a 10 and 25 man version. Dropped from Naxxramas, the Obsidian Sanctum and from Archavon the Stone Watcher in the Vault of Archavon.
 * Tier 8 - This set has a 10 and 25 man version. Dropped from Ulduar, and from Emalon the Storm Watcher in the Vault of Archavon
 * Tier 9 - This set has a 5, 10 and 25 man version. The 5 man version is obtained through Justice Points. The 10 and 25 man versions are obtained in Trial of the Crusader, and from Koralon the Flame Watcher in the Vault of Archavon.  T10B is purchased with tokens from 25-man normal and 10-man Trial of the Grand Crusader.  T10C is purchased with tokens from 25-man Trial of the Grand Crusader.
 * Tier 10 - This set has an A, B, and C version. The A version is purchased with Justice Points. The B version is purchased by turning in the A version plus a token obtained from Icecrown Citadel 25-man normal or 10-man heroic bosses. The C versions require the B version plus a token obtained from 25-man heroic boss kills. The A and B versions can also be obtained from Toravon the Ice Watcher (10-man raid for A, and 25-man raid for B) in the Vault of Archavon.

PvP Gear Sets

 * Season 9 - This season began on December the 14th, one week after the release of Cataclysm.

Dungeon Sets
There were no new dungeon sets released with Cataclysm.

Raid Tier Sets

 * Tier 11 - This set has a Normal and Heroic version. The Normal version is purchased with Valor Points and Class Tokens. This armor set is associated with Bastion of Twilight and Blackwing Descent.

Sets by Class

 * Death Knight sets
 * Mage sets
 * Priest sets
 * Rogue sets
 * Warrior sets
 * Druid sets
 * Hunter sets
 * Paladin sets
 * Shaman sets
 * Warlock sets

= Non-Class Sets = Non-class sets are not restricted by class. Any class that is qualified to wear the armor type can wear the set. Technically, all Dungeon 1 and all Dungeon 3 sets are non-class sets, as they don't have a class requirement. However, some sets, including all Dungeon 1 and some Dungeon 3 sets, are aimed at specific classes due to the bonuses on the sets. All non-class sets give extra bonuses when wearing multiple pieces of the set.

Low level sets
The following sets are available to players leveling up to 60.

Instance sets
The following sets can be found in Scholomance.

The following sets are Cloth class sets.

Anti-Scourge sets
The following sets were available to fight the Scourge invasion. Since the invasion has ended, the sets are no longer available. Each set occupied the same three slots: chest, hands and wrist.

Arathi Basin sets
Those sets are available at Arathi Basin vendors. They are class-restricted, thus can only be worn by the listed classes. Each set uses the same three slots: feet, waist and shoulders.

Quest sets
The only quest set so far is the Twilight Trappings set.

Uncommon crafted sets
The following sets are craftable. They are designed for players leveling from 60 to 70.

Rare crafted sets
The following sets are craftable. They are designed for players at or near level 70.

Epic crafted sets
The following sets are craftable. They are designed for advanced level 70 players.

Resistance sets
The following sets provide high resistances against a school of magic. They are craftable.

Dungeon Set 3
Some sets of Dungeon Set 3 are not designed for particular class. Each set uses the same five slots: chest, hands, head, legs, and shoulder. They are as follows:

Anti-Scourge sets
The following sets were available to fight the second Scourge invasion, shortly before the launch of WotLK. Since the invasion has ended, the sets are no longer available. Each set occupied the same four slots: chest, hands, legs and shoulders.

Uncommon crafted sets
The following sets are craftable. They are designed for players leveling from 70 to 80. Each set uses the same eight slots: chest, feet, hands, head, legs, shoulder, waist, wrist.

Rare crafted resilience sets
These sets are designed for players who want to pvp at or near level 80. Each set uses the same eight slots: chest, feet, hands, head, legs, shoulder, waist and wrist.

World of Warcraft: Cataclysm (Level 85)
There were no new crafted sets released with Cataclysm.