fget is a commandline tool for mirroring remote files via FTP. It is based upon the included FTP client library, whose API is designed to resemble the normal Unix API for accessing files and directories. This interface should make it very easy to integrate FTP support into other applications.
tnftp (formerly known as lukemftp) is a port of the NetBSD FTP client to other systems. It offers many enhancements over the traditional BSD FTP client, including command-line editing, command-line fetches of FTP and HTTP URLs (including via proxies), command-line uploads of FTP URLs, context-sensitive word completion, dynamic progress bar, IPv6 support, modification time preservation, paging of local and remote files, passive mode support (with fallback to active mode), SOCKS support, TIS FWTK gate-ftp server support, and transfer rate throttling. tnftp is the default FTP client found in FreeBSD, MacOS X, NetBSD, and SuSE Linux.
oftpd is designed to be as secure as an anonymous FTP server can possibly be. It runs as non-root for most of the time, and uses the Unix chroot() command to hide most of the systems directories from external users--they cannot change into them even if the server is totally compromised. It also contains its own directory-change and directory-listing code (most FTP servers execute the system "ls" command to list files).
tnftpd is a port of the NetBSD FTP server to other systems. It offers many enhancements over the traditional BSD ftpd, including per-class configuration directives via ftpd.conf(5), RFC 2389 and draft-ietf-ftpext-mlst-11 support, IPv6, transfer rate throttling, and more. tnftpd was formerly known as lukemftpd, and earlier versions are present in Mac OS X 10.2 (as ftpd) and FreeBSD 5.0 (as lukemftpd).
linux-ftdp-ssl is the netkit ftp server with encryption support. ftpd-ssl replaces normal ftpd using SSL authentication and encryption. It operates together with normal ftp. It checks if the other side is also talking SSL, if not it falls back to normal ftp protocol. Advantages over normal ftp(d) are that your passwords and the data you send will not go in cleartext over the line, and nobody can get it with tcpdump or similar tools.
ftp-ssl is similar to the standard FTP client and it interoperates with normal ftpd, but it uses SSL authentication and encryption. It checks if the other side is also talking SSL, and if not it falls back to the normal FTP protocol. Advantages over normal FTP include encryption of passwords and transmitted data, preventing network sniffers from acquiring secret information (most notably passwords).
KindFTP is meant to be a complete implementation of the FTP protocol, as specified in RFC959. It provides a component that directly exposes the low-level protocol, and it supports the core protocol that is available on most Open Source FTP servers. It has untested support for ACCT, SMNT, REIN, TYPE, STRU, MODE, ALLO, and SITE command. It uses iContract to provide a full formal specification of all software, jUnit for all unit testing, and Ant as a build tool.
Weeble File Manager (WeebleFM) is a PHP file manager that operates through an FTP connection. It offers a wide variety of functionality and is similar to the Web-based file managers used by Tripod and Yahoo. WeebleFM gives Web-space providers the chance to offer their clients a quick and easy alternative to FTP, TELNET, and SSH.