Looting

Looting is the action of taking items off of monsters ingame after you kill them, or otherwise receiving recompense from the quest other than the reward offered by the questgiver. Unlike most MMO's, in DDO most monsters do not drop actually drop loot. Instead most loot is gained from treasure chests.

Chest level
Chest level is usually equal to the quest's Normal CR, -1 on Casual, +1 on Hard, +2 on Elite, +any current global or personal loot boosts. Some chests are special and can have higher or lower level loot than indicated by quest level. "Ransacking" a chest (i.e. looting it too many times in too short a period of time), will decrease the loot level.

Treasure tables go up to chest level 31.

Above 25, lower level things on the tables begin to be cut out.

To get the really special items, quests need to be run on Epic Elite, with loot boosts.

Breakables
With Update 16 all breakables can now drop a wider variety of items, including equipment. (Common: Money, Gems. Uncommon: Potions, etc. Rare: Items. Very Rare: Tomes)

Challenges
Chests in Challenges are capped at CR 25.

Personal
Jewel of Fortune and Pirate Treasure Map: Only affects the level of loot for the player who has the effect when they open the chest. It does not affect the level of loot for anyone else in the group.

Group
Greater Dragonmark of Finding: Provides a +1 loot boost for entire group. See: Dragonmark of Finding for more information.

Options/ rewards based on player class
On quest end reward lists that are entirely random, and have no chance of any named or special items appearing (including crafting ingredients such as from Necropolis or The Vale of Twilight), if the Class-Based End Rewards option is checked on, it will restrict the base type of the items that appear to specific types based on your class.

It has no function on any reward lists that can include any named items or special ingredients, and it does not restrict the effects that can appear on an item- only what types of items you'll see.