Microsoft OneDrive!

Syncthing replaces proprietary sync and cloud services with something open, trustworthy and decentralized. Your data is your data alone and you deserve to choose where it is stored, if it is shared with some third party and how it's transmitted over the Internet.

You should have full control over your data. We help you achieve that: a safe home for all your data. Secure, under your control and developed in an open, transparent and trustworthy way. We are Nextcloud.

SpiderOak provides an easy, secure and consolidated online backup, storage, access, sharing & sync tool for Windows, Mac OS X, and Linux (Ubuntu, Debian & Fedora). SpiderOak offers a different approach to online backup, synchronization, and sharing. This difference is not just measured in our zero-knowledge privacy policy - the first one ever employed in this setting - but also in our flexible design in handling data from all platforms (Mac, Windows, Linux) and locations (external drives, network volumes, USB keys) in one centralized account. »

Files on Yandex.Disk won't get lost if your phone or computer breaks. You'll have enough storage space for your most precious photos and important documents.

Seafile is a file hosting software system. Files are stored on a central server and can by synchronized with personal computers and mobile devices via the Seafile client. Files can also be accessed via the server's web interface. Seafile's functionality is similar to other popular services such as Dropbox and Google Drive, with the primary difference being that Seafile is free and open-source, enabling users to host their own Seafile servers without artificially imposed limits on storage space or client connections. »

SugarSync lets you synchronize, backup and remotely access files and folders across your PC or Mac. You can also remotely view files from Windows Mobile, Blackberry, iPhone, Symbian and Android.