Phase Spider blood is nice because it's Superior Invisibility which is a solid 10 minutes. I didn't bring it up because I consider it a potion (it comes up in the Bazaar as a potion as well). Amusingly, I have one in my shared bank for emergancies. So far, neither my mage, bard nor rogue have needed it
I forgot about Larrikan's mask. IIRC, you need to be lvl 51 to click it though which might diminish its usefulness though. At least, the "level for effect" on it now says 51 -- I dunno if it lets you cheat or not like potions with high "level for effect"s.