Search: attachments.
It would be nice to search issues with/without only attachments. More advanced would be to also search for a specific / wildtag / regex named attachment.
Attachments are linked uploads, probably need to either search for the current instance's upload links (performance intensive) or have a database entry for (probably csv) list of attachment names.
The name is determined by the uploaded file and markdown (user might change the name and refer to the file by that name). Since the display name is already in normal text search, probably the best way is to only include the original filename.
Same filename in one issue should be fine with multiple duplicate entries in csv. Performance while searching can be saved by looking if the field is empty and skipping it in the search.