libssh is a C library to access SSH services from a program. It can remotely execute programs, transfer files, and serve as a secure and transparent tunnel for remote programs. Its Secure FTP implementation can play with remote files easily, without third-party programs other than libcrypto (from OpenSSL) or libgcrypt.
JFTP is a graphical FTP client that allows you to transfer files securely over the Internet using FTP and SFTP. It includes support for all basic and advanced FTP tasks, support for SSL with 128-bit encryption, multiple concurrent FTP sessions, a secured favorites manager, and a certificate manager. Internationalization and localization is fully supported, and multiple deployment options are available, including standard installation, a Java Applet, and Java Web Start.
FSP is a UDP-based protocol for transferring files. It has many benefits over FTP, mainly for running anonymous archives. It is usable on lines with high packet loss ratio (70% WiFi), can go behind firewalls and unnoticed by port scans (because of UDP), does not overload networks when hosting ISOs or movies, share files on modem lines without eating all of the bandwidth, and keeps lamers away from your site (they don't know how to get to it). This project is active continuation of the FSP code base (abandoned 1996-2003).
CrossFTP Client is a multi-tabbed FTP and Amazon S3 client supporting SFTP, FXP, WebDav, MobileMe iDisk, and Amazon S3. It uses a two-pane interface. It features multiple tabs, multiple threads, scheduling, synchronization, remote editing, archives support, anti-idles, and much more.
Rad Upload is a drag and drop file upload applet with a progress monitor. Advanced features include recursive upload of directories and setting upload limits at the client side. Bandwidth saving options include filtering out unwanted file types, compression, and resizing images before they are uploaded. Both HTTP/HTTPS and FTP protocols are supported, and files can be uploaded using copy and paste, as well as with an optional traditional browse button.
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.