Chest

Locked Chests
The landscapes of Tyria, Cantha & Elona are dotted with randomly positioned locked chests, which are guaranteed to contain uncommon or rare items. Whenever your party finds a new, locked chest, multiple party members can each use their own keys to unlock the chest and get their own loot. Monsters randomly drop chest keys, and you can also buy chest keys from Merchants. Chests differ in regions and can only be unlocked with the appropriate key.

A player can open a chest with the corresponding key (i.e. a Krytan Key will open a Krytan Chest). Whoever opens the chest is granted a piece of loot. Therefore, if you open a chest it is not possible for the loot to be assigned to anyone else in your party. Usually, the farther through the game you are the better the loot becomes. After the October 25th, 2006 update, the chest loot is now randomized for each player.

Be wary however, as virtually every chest you come across will be guarded by a group of enemies, so if you see a chest that seemingly has nothing nearby, expect something to crawl out of the ground when you approach it.

Unlocked Chests
In Pre-Searing, players will find lots of unlocked Hidden Stashes. But in Post-Searing, unlocked chests are very uncommon. However, in the Ascalon region players will find piles of Wreckage that may contain some gold or goods.

Unlocked chests are chests that do not require a key, and can be opened by anyone. However, the loot can be assigned to anyone in your party, including henchmen. In the Realms of the Gods, completing a quest will usually reveal a chest near the reward giver that is also an unlocked chest.

Note: While doing the quest Kilroy Stonekin, Sorrow's Furnace will produce three unlocked chests. These chests are not normally part of the area and will not be there without that quest.

Note: There used to be two unlocked chests in Dreadnought's Drift, as well as one in Ice Floe just outside the exit from Thunderhead Keep. These were removed in the March 2nd update.

Mission/Quest Chests
Several quests include chests (e.g. the quest "The Royal Papers"). These are unlocked and reveal quest items when opened.

Prophecies campaign

 * Chest - Gates of Kryta (Mission) which contains the Orrian Text
 * Chest - Deldrimor Bowl (during The Deserters quest an empty chest will appear)
 * Chest - Sorrow's Furnace (during Kilroy Stonekin (Quest), 3 chests with loot for the party)
 * Chest - Sorrow's Furnace (during Tasca's Reprise quest 5 chests will drop from monsters with the Quest Items required to complete this quest)

Factions campaign

 * Chest - Monastery Overlook (this chest is unlocked by Instructor Ng at the start of a Canthan character's training, inside is the Starter weapon for that character's primary profession)
 * Spirit Keepers (sic) - Panjiang Peninsula (these chests appear during the Shackled Spirits quest, and contain Shackled Spirits)
 * Chest - Kinya Province (this chest contains the Ornate Box needed for the quest Lo Sha's Gift)
 * Old Chest - Wajjun Bazaar (this chest is there all the time, but is only opened during the quest Little Lost Bear)

Nightfall campaign

 * Chest - Barbarous Shore, in the Corsair camp, contains a Preserved Red Iris Flower
 * Torc'qua Chest - City of Torc'qua, once you defeat Lord Jadoth, contains a Margonite Gemstone for each party member1


 * 1) Torc'qua Chests (and presumedly the other overlord chests) work like locked chests except that they don't require a key and always provide the same item.

Core

 * Chest - winning the Hall of Heroes in the Global Tournament will spawn a chest that drops high level loot. This chest drops Celestial Sigils, as well as certain rare weapon skins such as Dwarven Axes or Crystalline Swords.
 * Chest - The Fissure of Woe and The Underworld (chests will appear after completion of a quest.)  Dwarven Axes have been known to drop from these chests in The Underworld

Images

 * 1)  = Low end
 * 2)  = High end