PuTTY is a free implementation of SSH and Telnet for Windows and Unix platforms, along with an xterm terminal emulator.
FileZilla is a feature-rich FTP, FTPS and SSH FTP client, with support for all major plattforms. All tools are designed to aid moving and synchronizing files between local and remote file or webservers. It even allows multi-target uploading or editing files in-place. FileZilla also sports IPv6, a tabbed interface, resuming up and downloads, transfer speed limits, large files over 4GB, server and bookmark management, drag and drop, filtering, HTTPS / SOCKS5 / FTP proxying, and remote file searchi
GNU wget is a HTTP and FTP downloading and mirroring tool for the command line. It provides various options and complete HTTP support. It supports REST and RANGE requests for partial and continuous downloads, can use wildcards for mirroring complete websites, converting HTML references to relative links, use HTTP cookies, proxies, persistent connections, background processing, and can compare files prior downloading.
Monikop provides an automated means for data transfer between two unconnected networks using removable disks.
curlcpp is a C++ wrapper around cURL/libcurl. It abstracts connections and transfers in a more user-friendly and object-oriented API, through curl_easy, curl_multi and curl_share. It provides tracebacks, and a curl_writer interface for output capturing, and simplified data transfer handling via curl_reader/writer.
Fldigi is a digital modem application for common amateur radio systems. It supports CW, PSK, MFSK, RTTY, Hell, DominoEX, Olivia, and Throb. It also helps calibrating a sound card to a time signal and perform frequency measurement tests. Flmsg is a messaging tool over digital radio, while Flarq supports ARQ file transfers.
gMTP is a simple graphical Media Transfer Protocol client. It supports all MTP based devices (MP3 and MP4 players, mobile phones, tablets). Besides file transfer and folder management, it can manage metadata and album art, playlist creation, or name the device itself.
ExtraPuTTY is a fork of Putty 0.63 for Windows. It adds a Win32 API, command shortcuts, uses config files instead of the registry, automatic reconnection, and supports FTP, TFTP, X/Y/Zmodem besides SSH and Telnet. It also provides Lua 5.2 scripting for session handling and management, and is directory relocatable for portable installations.
File Service Protocol is a lightweight UDP-based file transfer system. It has many benefits over plain FTP, such as anonymity for transfers and archives. It's less bandwidth intensive but still fault tolerant.