ProFTPD!

Very secure FTP Daemon, a secure, fast FTP server for UNIX systems, including Linux.

Serv-U is the FTP server that is both secure and easy to use. Sharing files through the Internet is a smooth process with the industrys most popular FTP server. The clear and comprehensible interface makes easy work of all your file sharing and management, and the SSL connections between Serv-U and your secure FTP clients will ensure that your data is encrypted.

Pure-FTPd is a free (BSD), secure, production-quality and standard-conformant FTP server. It doesn't provide useless bells and whistles, but focuses on efficiency and ease of use. It provides simple answers to common needs, plus unique useful features for personal users as well as hosting providers.

Syncplify.me Server! is the free FTP, FTPS, and SFTP server for Windows by Syncplify, Inc.Powerful, secure, yet very easy to configure, this software simplifies regulatory compliance and operation of a secure file transfer server.Its main features are: support for plain FTP, explicit FTPS (TLS), implicit FTPS (SSL/TLS), and SFTP file transfer protocols, basic secure shell (SSH-2) and forwarding tunnels support, runs as a system service, supports large files (> 4 GB).And it also has several useful advanced features like: PKI authentication with multiple key-pairs per user, advanced FTP(S) and SFTP security settings, configurable automatic blacklist, real-time monitor, virtual folders with per-folder security, IP-based and per-user security (white-lists), powerful event-handling subsystem, graphical Configuration Manager, command-line Interface (CLI) configuration tool.It is totally free, including lifetime updated and upgrades, for personal use. »

BPFTP Server is a powerful Windows FTP Server that's easy to install and manage. Total control over connected users and where your files go. All features available from an easy to use graphical interface! The most BulletProof way to distribute files.

A portable FTP server that allows definitions of several users with root directory and virtual directory, plus quite powerful control permissions.

Windows FTP Server with SFTP and SSL. Includes events automation. Recommended by Cisco for CUCM backup. Offers an optional Web Interface.

CrushFTP is a robust file transfer server that makes it easy to setup secure connections with your users.

War FTP Daemon is a popular free FTP server, written by Jarle (jgaa) Aase in Norway.

SFTPPlus provides server & client software for managed file transfers using protocols SFTP, FTPS, FTP/S, HTTPS, SSH, PGP, SCP.