This list defies NPOV, No Original Research, and WP's standards on Notabilty
First of all, the word "Unusual" is highly problematic as it is a very subjective word, on par with "good", "bad", and "normal". A death that may seem unusual to one person may not seem so to another, and even within different contexts of data may lose its seeming unusualness.
If we were to change this article's title to "List of deaths generally viewed/cited as unusual", we still would be doing original research, and this would still be only presenting a biased view.
If we were to change this article's title to "List of deaths refered to as unusual", all the remaining entries will be sourced, however, these will be hard to find, and barely representative of the subject, and be mostly lifted from published personal opinions. (Although this option will satisfy verifiability).
And if we were to change this article to focus soley on statistically unusual deaths, the whole article will have to be rewritten to include rare diseases, rare instruments of destruction, etc,etc. In addition, what aspect of the death and in what context will we look at look at to declare it statistically unusual? (Of course, this will violate NOR)
And lastly, the subject of the list itself, "unusual deaths" is hardly notable at all. It may often pop up in trivia books (which often repeat many myths and unverifiable factoids), but this subject, by itself, does not meet WP:NOTE.
In this discussion, please avoid arguments such as "It's interesting", "It's useful", "It's entertaining. For help, read WP:AADD.
I know people are very much attached to this content, but please, this does not belong on WP. There are other wikis with not such stringent guidelines that may be better places for this bit of trivia, such as [1], [2], and [3].