There are also a few projects where I think all observations could safely be marked dead. The first three that come to mind have over 10K observations together.
https://www.inaturalist.org/projects/skulls-and-bones
https://www.inaturalist.org/projects/skulls-and-bones-new-zealand
https://www.inaturalist.org/projects/skulls-skeletons-s-afr
Edit: I forgot the roadkill projects, that’s easily another 15K+, e.g.
https://www.inaturalist.org/observations?project_id=california-state-roadkill
https://www.inaturalist.org/observations?project_id=roadkills-of-texas
https://www.inaturalist.org/observations?project_id=global-roadkill-observations