Equipment, Consumables, Items.

This will be an on going project for me to document all items that have useful applications in dungeon settings. I will most likely achieve this by going area by area checking all heart vendors, merchants, and events on 8 characters as I complete these areas to ensure I don't miss anything. Where possible experiments will be documented to provide the most information possible. Any and all links to existing items or articles on the subject would be appreciated.

Dulfy has already posted lists of these items on his website. A link to her website can be found on the Useful GW2 Links post on these forums.

Here are the lists of item guides that have been posted:
GW2 Useful and Fun Consumables guide
Guild Wars 2 Karma Vendor List
GW2 Cooking Material farms
GW2 Cultural armor and weapons guide

I thought Dulfy was a chick. >.>

Dulfy is a she, yes

On hold.

I carry a "kit" wherever I go: 
Ash Legion Spy Kit (nerfed but still useful).  Cooldown is 60s on stealth skill.  Does not give Stealth buff effect or "Revealed" debuff.  Must not move more than ~2 steps or stealth drops.  Can be used in dungeons.
Fire Elemental Powder (summons a powerful fire elemental equivalent to or better than the elite Elementalist summon, can be respawned immediately upon death, lasts 5 minutes otherwise).  VERY useful for low level characters, the run to Fireheart Rise can be completed solo on any class at any level.  VERY useful at all levels, can be used in dungeons.

On some characters I carry some odd items:
Experimental Telportation Gun:  No longer usable in dungeons.  Good for hilarious effect.
Experimental Rifle: Has a Jump Shot that stealths you on landing.  Targeted.  Useful for classes without jump skills of their own.  Also has a basic attack that blinds.  Relatively difficult to acquire.  Works in dungeons.
Hylek Dart Gun / Poison Pistol: 3 attacks that do basically no damage, but inflicts a LONG poison duration on the target.  Can create a cloud of poison for AoE poisoning.  Can be used in dungeons.  Can be dropped for other players.
Jar of Bees: inflicts a UNIQUE CONDITION called Angry Bees.  Does damage about equivalent to a single bleed stack.  Does not appear to stack duration or effect.  Can be used in dungeons.  Can be dropped for other players.
Fireworks:  yeah I'm sure you know what these do.  Nothing at all.  Can be used in dungeons.  Can be dropped for other players.
Cattle Prod: HILARIOUS.  Has an attack called "Prod".  Can be used in dungeons.  Can drop for other players.
Rotten Drake Egg: grants Might, can stack up to 25 if you have +boon duration, but there is an animation.  Can be used in dungeons.  Can drop for other players.
Mini Golem in a box: fires a seeking golem missile.  Looks hilarious, actually does decent damage.  Can be used in dungeons.
Ogre Pet Whistle:  Summons a random animal.  Dies easily, but can be ressurected.  Cannot summon another until corpse disappears.  Not actually very good.  Lasts 5 minutes.