On this page an overview of Android apps.
Ftopia (5 GB free storage)
G Cloud Backup
HiDrive (5 GB free)
pCloud (10 GB free)
Quiver (100 GB free)
Right Backup (0,1 GB free)
STACK (1000 GB free)
Sync (5 GB)
Syncplicity (10 GB free)
TeamDrive (2 GB free)
Touro Cloud Backup (3 GB free)
Tresorit (1 GB free)
WEB.DE Online-Speicher (2 GB free)
Yandex.Disk (10 GB free)