MkDocs will copy any files in your docs_dir to the site. However, MkDocs will not do anything else with non-markdown files. If you would like to auto-generate a list of files, then you would need to use a plugin for that.

Are you looking for something like Apache's Options +Indexes ? or
https://vercel.com/docs/edge-network/directory-listing

I know someone who blogs on MkDocs.
He seems to have manually generated a list of articles in index.md.
This idea can also be a means of auto-generation.

Ideally, it will be produced as a plug-in.

Added to Wiki. Expect the development of plugins:
https://github.com/mkdocs/mkdocs/wiki/Plugins-Ideas

Originally this post was on an issue, but it has been moved to the recently set up Discussion:
#2322

Please continue to comment here if necessary.

... and I'm a MkDocs User, but I've included this comment. 💻😆

Maybe awesome-pages is what you want?

I think this will change the way MkDocs is used. This can compete with other static site generators.

If it is possible to display images, for example, it will be possible to display a list of themes. Instead of here:
https://github.com/mkdocs/mkdocs/wiki/MkDocs-Themes

You need to consider how to post the theme.

but anyway, you will be able to use MkDocs for quite a variety of purposes.

https://github.com/oprypin/mkdocs-gen-files plugin can do this

Untested code, to be put in a script as per the plugin:

import os
import mkdocs_gen_files

with mkdocs_gen_files.open('some_dir/files/index.md', 'w') as f:
  for filename in os.listdir('docs/some_dir/files'):
    f.write(f'* [{filename}]({filename})')

Shameless plugin: I wrote https://github.com/skedastically/mkdocs-macro-gimmicks/ which can {{ listfiles() }} in a page's current directory