The Files On-Demand capability is now coming on Mac devices with the incoming OneDrive for Business client update for Mac.
The Files On-Demand allows you to synchronize your OneDrive for Business and SharePoint Online content without having to download the complete content.
To take advantage of this new capability for Mac users, you need to run macOS 10.14.2 or later and have the update OneDrive client (version 18.240.1202.0001 or higher).
You can get the updated version here https://aka.ms/MacFilesOnDemandBinary
You can get the updated configuration settings for Mac here https://docs.microsoft.com/en-us/OneDrive/files-on-demand-mac