Support to select from already uploaded files

Initial checklist

• I understand this is a feature request and questions should be posted in the Community Forum
• I searched issues and couldn’t find anything (or linked relevant results below)

Problem

Over time, users have uploaded many files on my server and with each request they are required to upload the file. I want to give a functionality to select from already uploaded files such as "My Gallery".

I see there are many closed issues https://github.com/transloadit/uppy/issues/856, https://github.com/transloadit/uppy/issues/450, and more on the similar requirement.

Solution

A plugin to allow loading files from external sources, such as your own server or third party. The select file should not upload again (or a config option can be given to allow reupload or not).

Alternatives

If there is no such feature yet, I want to place an additional button on the UI "My Gallery", clicking will execute an external method that will further handle the fetching and selecting the file.

This I can achieve by placing a button outside the UI, but I want it inside the UI. Is there an option to customize the UI? There is this documentation link https://uppy.io/docs/guides/building-your-own-ui-with-uppy/ but it has no content.