Air Explorer

Air Explorer is an application that manages easily all your cloud servers (Google Drive, OneDrive, Dropbox, Mega, Box, Mediafire, WebDAV, Copy, Yandex,...).
It transfers files between the clouds, synchronizes folders between any cloud or your computer and, optionally can encrypt your files when you upload them to the cloud.
Moreover, it supports multiple accounts from the same server and centralizes the search of your files across all the clouds.
Air Explorer makes all your clouds work as one, allows drag'n drop files between your computer and the clouds and, copy/paste between cloud servers and pause and continue uploads and downloads.
It doesn't lose the clouds features like thumbnail view of the pictures and sharing files.
It works with a plugins system to add cloud servers.