It's me again, thought I'd contribute another item of mine that could help some people out. This one actually is useful, although it is just as fun as the Protovoltaic Magneto Collector.
As most people know, almost all stuns, sleeps, pacifiers, etc. have their duration shortened down when used in pvp against another player. However there is one that is not. It's name is Sablemane's Sleeping Powder, and it's from a quest chain.
To get it in the first place, you have to kill the npc Dorgok, he should drop an item called Gorgrom's Favor that starts the quest chain to get the powder(you only get one powder each time you pick up the quest, but each one has three charges).
After doing two quests after that, one being just to talk somebody, and the other just to get 7 drops from level 66 mobs. Once those are out of the way, you should finally be able to get the quest Goodnight, Gronn. It will give you the powder, and after that you can just abandon and re-get the quest as many times as you want.
Anyways, what it does: Because of the fact it's supposed to be only used on a specific quest mob, it doesn't follow the normal pvp rule, and the duration will always be 30 seconds (Unlike Magic Dust, Slumber Sand, etc). Second off, it has no cooldown. You can re-apply it as many times as you want on as many things as you want.
If you're sick of getting 3v1'd even the playing field a little bit, or turn a 2v2 into a 2v1. Also, although it takes a little bit longer, you could just do something like Frostbolt, Sleep, Frostbolt, Sleep, Frostbolt, Sleep, etc. And if they trinket or break out of it, just apply it again!
I hope some people can have fun with this, and think of some new ways to use it. Also, if i was supposed to make this in one post with the Magneto Collector, I apologize, it's just they are two completely different items, and they had seperate uses as well.