MacOS: Thumbnail preview for all media files when "Files on demand" is enabled.
Works on Windows Explorer and OneDrive - why not do this on the OneDrive.app for the Mac? Dropbox has created a "hack" for this by creating their own small Thumbnail preview icons for all media files when "Smart Syncronization" is enabled. OneDrive for Business needs this feature to be competitive. When listing a folder of .JPG .PSD .IND etc. you shouldn't have to download 1GB of files before you can see a thumbnail version of your document.
Create these on the Sharepoint backend and let OneDrive use these small icons as thumbs for quickly identifying files.