World Hyperinflations, a recent working paper by Steve Hanke and Nicholas Krus, is exactly what the title would suggest: An attempt to collect data on every hyperinflation on record. They count 56, possibly 57, and Hanke has since suggested that Iran is on the way to becoming number 58.
You might assume that these events are already well documented, but there have been few serious studies, despite the popularity of the topic. To quote the paper: