I developed this checklist after discussions in 2014 on the community forum. It remains a work in progress and I update it every 6-12 months. It started life based on the IUCN’s Red List but now also triangulates with more recent taxonomies from the Handbook of the Mammals of the World and the American Society of Mammalogists’ Mammal Diversity Database. It includes a few exceptions for ‘new’ species that I believe are in the pipeline. Differences from the IUCN list are generally highlighted in yellow. The taxonomic order largely follows Wilson & Reeder’s Mammals of the World (2005, Johns Hopkins University Press).
The spreadsheet also lists changes made over time since I started it.
Here is some interesting discussion on differing taxonomies that influenced the presentation of this list.