Acceptable evidence of death needs to come from some official or semi-official source such as an entry on a death-registration / grave / cemetery / obituary site. A website link (URL) should be provided wherever possible. Regrettably personal recollection is not sufficient to show that we have done our best to protect people's privacy.
If you are in any doubt as to whether your evidence of death would stand up, then hold back the identifying details, and describe the type of evidence so that other users can help you assess it via comments.
What is an example of "acceptable evidence of death" for someone born less than 100 years ago that you think could be presented in a question at G&FH SE?
If you wish to present more than one please do so in separate answers.
I am asking this question because several other recent Meta Q&As have been debating whether links to public documents, redacted images, etc should be permitted, or not. In particular Allowing links to public documents that contain living people is about whether links to images that mention potentially living people can be used to help frame the question for potential answerers. This question is not about bringing new information into a question it is about how to provide evidence that someone identified in the question body is deceased.