If you need to connect to an (S) FTP, you usually use a dedicated client to do so. If you are a Google Drive or Dropbox user, you probably use its official Mac app.
But there is now a single app that integrates with all of this natively, in the Finder. O CloudMounter, released today by Eltima Software, allows you to mount remote drives in the Finder and browse them as if they were local.
CloudMounter is compatible with Microsoft OneDrive, Google Drive, Amazon S3 and Dropbox, as well as (S) FTP and WebDAV servers. You easily register all your accounts, which are accessible with two clicks from the OS X menu bar.
The CloudMounter interface itself is your account setup window, as the services integrate with the Finder itself, which is the coolest part of the software.
CloudMounter costs $ 30 and can be downloaded in reverse trial on here.