Also if your output format is LaTeX things will probably look better if you wrap the text of any footnotes containing lists, tables or code blocks in a minipage:
````markdown
[^fancy_note]: `\begin{minipage}{0.8\textwidth}`{=latex}
* List
```code
a = b
```
More
`\end{minipage}`{=latex}
````
To make writing easier and to make output more uniform you may want to use a Lua filter to "automatically" wrap the text of all footnotes in such a minipage:
````lua
local before_note = pandoc.RawBlock('latex', '\\begin{minipage}{0.8\textwidth}')
local after_note = pandoc.RawBlock('latex', '\\end{minipage}')
function Note (note)
-- arg #2 is position to insert before
table.insert(note.content, 1, before_note)
-- no position == append at end
table.insert(note.content, after_note)
return note
end
````