http://www.curse.com/addons/rom/etargetlist
If you can see someone's health bars, you can see them on etargetlist, in one simple list. It would be ultra handy for siege, the problem is that it also puts pets in the list, NPC's, wardet pets, etc. Making it a waste of an addon.
If someone could make it so only enemy players (or at least the option) appear on the list, it would make this addon amazing.
Further, making it so you can see people's specific buffs (kinda like how gridcliqueit works) next to their name on the list, would be amazing
(Gridcliqueit will allow you to see player debuffs without having to click on them (like raid frame) but this may be impossible since the only way a player can see an enemy's buffs are by clicking on them)).