This may exist through some kind of theming tool, but I haven’t run across it so far.
Use case or problem
When using significant numbers of attachments (images, PDF, etc.) the file view can get very cluttered. It would be nice if there was a toggle to limit the files shown in the explorer to *.md only.
Proposed solution
An additional button in the top section next to New Note, New Folder, Sort order which toggles between an all files view and a .md only view similar to the edit/view toggle icon use on articles.