Drive Union

Browse/manage multiple cloud storage service/accounts all together.

Supported cloud drive services - OneDrive - GoogleDrive - Dropbox - Box - (May add more in future)

This app provides productive browsing/manipulation by - Drag & drop from/to Explorer/Desktop - Drag & drop for inter account/services - Optimized for desktop experience (Explorer-style viewer with tree view) - No locally synch'd files, So no local disk space required - Search across all registered storage at once - Nice image & video viewers optimized for fast streaming browsing

Up to 3 accounts/service with free edition. You can unlock it by in-app purchase

I recommend you to take a look at this very short video to quickly see it. https://youtu.be/q5isMIwikVs