EZ-Thro Dynamite

These should be on the AH more often. They come in useful for high lvl chars wanting grind rep or unlock loremaster by doing low level quests, as some of them (namely Unbidden Vistors in Durotar) block progression in the quest chain until they are completed.

Another I can think of is in Ogre Abduction in Feralis, where you need to get it to low health but not kill it.

Higher levels have isssues with one-hitting everything, even when unequipped, so a set damage item like this is a godsend.