Android Send to Dropbox is a target for all Android applications that accepts all kinds of files and stores them in a folder in your Dropbox. Accounts are managed securely in Accounts&Sync. It supports multiple accounts.
Droper is a Symbian Dropbox client that allows Dropbox users to access and modify their synced files and folders. It can also be used as a light-weight Dropbox client for desktop platforms like Windows and Linux.
Balloon is an alternative to DropBox with file version control. It is based on Mercurial and supports Git. Local repositories on different hosts are automatically synchronized with a remote repository thanks to the inotify API.