We are very fortunate to have our own icons on DPO but this topic is for all the ones that are not here (many because they are, well, no longer alive and PDO has not managed to penetrate into that hallowed space yet

).
Here is a great web site to start off - its for Bridget Mayer's book but has collage of ballroom icons that you can mouse over to get their names:
http://www.ballroom-icons.com/Take a look, its fascinating...