PTFTP is a basic and lightweight FTP client for Windows PCs.
electerm is a Terminal, SSH, and SFTP client with hotkeys support for the most popular desktop platforms.
Truck is an FTP tool that uses advanced technologies to make data downloading and uploading faster than other such tools.
Besides being an FTP client, Cyberduck allows you to connect to a number of cloud storage providers and lets you browse and exchange files to and from your computer easily and conveniently for free.
WinSCP is a free and open source FTP client with tons of features for Windows.
FileZilla is an FTP client that lets you upload and download files from an FTP server on Windows, Mac, and Linux machines.