Here is the list of Free 3rd Party Popular Clients:
Windows
1.) Filezilla 3.5.3
Windows XP, Vista and Windows 7 are supported, each both 32 and 64 bit.
2.) CyberDuck 4.2.1
Windows XP, Windows Vista or Windows 7 required.
3.) WinSCP 4.3.7
4.) FireFTP
FireFox Browser required.
Linux:
1.) FileZilla 3.5.3
Built for Debian 6.0 (Squeeze). It is highly recommended to use the package management system of your distribution or to manually compile FileZilla if you are running a different flavour of Linux.
MAC OS X:
1.) FileZilla 3.5.3
Requires OS X 10.5 or newer
2.) CyberDuck 4.2.1
Universal Binary. Mac OS X 10.5 or later required. Works with 10.7 Lion.