LeechCraft is a cross-platform modular "internet-client" application.
It has plugins that allow one to browse the web, chat via instant messaging (like Jabber or IRC), read RSS/Atom feeds, download files via BitTorrent, Direct Connect and other protocols, play media files and much more.
GiraffeFTP is a Java based FTP client and server. It includes GUI and command line tools. Good code to see to understand the FTP Protocol and sockets. Also includes a non-standard implementation of SSL sockets.
cmdftp is a command line FTP client for Unix systems that features shell-like functions, passive mode, local and remote transparent modes, broken connection resumption, multiple and recursive file transfers, auto-login, and large file support.
This assembly is a client component to communicate with a
given FTP server. It has no GUI but rich underlaying functionality
like detailed listing, recursive upload, download and deletion.
It also supports BINARY/ASCII transer type and ACTV/PASV mode
Ftp4net is a C# class for communication with FTP Server, which conforms to the RFC 959 (FTP). It\'s an API that handles all FTP protocol commands. This class is designed for creating FTP Client software with .NET