Poison created from the Ocean of Milk in Hindu mythology as a byproduct of the development of the nectar of immortality. Turns your throat blue; curable by having your wife squeeze your neck. Excellent; original.
Poison allegedly developed in Sicily in the 17th century which "contained mostly arsenic and lead, and possibly belladonna....the legend that Mozard was poisoned using Aqua Tofana is completely unsubstantiated, even though it was Mozart himself who started this rumor." Fatal on the fourth dose; appropriately unique.
Attributed to the Borgias, no contemporary record aside from a description of a "white powder with a pleasant taste." Indistinct, unimpressive despite the Borgia association; possibly just a misunderstanding of sugar.
Poisoned coffee popular among government officials of Qajar Aran; according to Wikipedia was responsible for taking out two grand viziers, which is no joke.
"Seeing that it was no easy task of creating such a lethal death through such a small amount of poison, it is speculated that there were probably few deaths from the poison rings." Disappointing.
Just another term for arsenic. Nothing special.