FileZilla is a powerful FTP-client. It has been designed for ease of use and with support for as many features as possible, while still being fast and reliable.Bundleware
Be aware that installing FileZilla on your computer might install some bundleware/malware on your machine. See this thread on the FileZilla forum: https://forum.filezilla-project.org/viewtopic.php?f=2&t=48441
WinSCP, a popular free SFTP and FTP client for Windows, copies files between a local and remote computer. It supports also FTPS, SCP and WebDAV. It offers easy to use GUI for all common file operations and a powerfull automation with .NET assembly.
A libre FTP, SFTP, WebDAV, S3, Backblaze B2, Azure & OpenStack Swift browser.
ForkLift is designed to be the fastest, most powerful file manager for the Mac. Connect to FTP or SFTP servers, manage your Amazon S3 account or your mobile devices over Bluetooth. All these features are beautifully integrated into a sophisticated, yet easy to use Cocoa based...
The gold standard of macOS file transfer apps just drove into the future. Transmit 5 is here. Upload, download, and manage files on tons of servers with an easy, familiar, and powerful UI. It’s quite good.
CarotDAV is a Simple WebDAV / FTP / SkyDrive / DropBox / GoogleDrive / Box / SugarSync client for Windows OS, available free of charge. It is also able to read GoogleDocs or IMAP.
My Commander (MyCO) is "the smallest - smartest - fastest file manager in the world", for Windows. Small and smart, MyCO uses less of your computer's memory while it's running.
gFTP is a simple GTK+ based ftp client for Linux. Supports the FTP, FTPS (control connection only), HTTP, HTTPS, SSH and FSP protocols, FTP and HTTP proxy server support, supports FXP file transfers (transferring files between 2 remote servers via FTP), UNIX, EPLF, Novell...