Filezela is an iOS app that allows you to transfer files across Cloud Drives, and support managing multiple cloud drives.

Features >
+ Manage as many clouds as you have
+ Transfer files from one cloud drive to another
+ File transfer in background.
+ Upload photos, videos from library to cloud
+ Rename, delete, copy files
+ Share files and folders easily with others
+ View documents, PDFs, photos, videos and more
+ Rich file browsing experience with high performance networking framework
+ Support for Dropbox, Box, GDrive, OneDrive and many more to come

Disclaimer >
This app does not provide content. By conforming to each cloud API Terms of Service, this app allows users to manage their files.