FileBrowser 

FileBrowser lets you create your own custom file browser.  You can modify the example code to present to your users just the data they need.

Currently myself I use the Audio tab.  By touching the orange circle I can play any audio tune in the list.  I prefer to have my music local and be able to play it without logging into any service or being bombarded with ads.

The Get SAF is an easy way to get a file off your google drive and download it to your cell phone.  So you can use this app as is to copy files back and forth to your google drive.