Most rare unique items for each difficulty

[Bughuul]

Let's list them.. no MI or greens.. only uniques please. Most rare ones.

Can someone say at least something a few of them?

[Medea Fleecestealer]

Well, most rare will be the ones that can't drop atm due to having the wrong level requirements on them.  Aionois, Ferrus Gnois I think, a few others.

[Bughuul]

Out of topic but, MI sabertooth with +1 rogue mastery is legit? Just dropped it, and never saw of it before.

[FunBun]

I'm trying to collect all the uniques in the game and sometimes it's frustrating to see yet another Ladon's Maw, Eye of Horus or some other unique item that always drops and not get the ones you're looking for. Strangely enough, I still don't have The Citadel while The Bulwark (both part of the same set) dropped a gazillion times. I find unique swords to not drop very often really.