Over on the Worldbuilding Stack Exchange, we help storytellers fill in the details of their world with plausible explanations. In many ways, we're a unique stack exchange because we answer hypothetical questions.
Our one big rule is that you have to be asking to create a fictional world; if you're asking a question about some field of study in the real world (physics, history, etc.) then go ask on that Stack Exchange site.
There's a class of hypotheticals that we're discussing, and the suggestion has been made that we should forward these questions to your site. I cannot tell from your Mythology Don't Ask help page whether or not you would reject the question.
Would the Mythology Stack Exchange approve or reject this question: "Given our world and a classical British Isles fairy myth, what is the best explanation for iron killing fairies?"
It asks for information about the real world, but it asks for fictional information about our world. If this were any other story world, it would totally be appropriate for Worldbuilding. We are considering allowing it, but we want to know if it would be better for your site.
This question is related, but here, we are asking for a mythological basis for myth, not a scientific basis for myth: Are questions about the scientific basis of mythology on topic?