OpenSSH
- Freely available SSH1 and SSH2 implementation. Designed as part of the OpenBSD project, but portable to a number of unix-like operating systems.
- http://www.openssh.org/

Psst
- An open source SSH client is available for download, as well as general SSH documentation and links to other secure communications projects. [UNIX]
- http://www.lysator.liu.se/~nisse/lsh/

FISH
- A free SSH client. [VMS]
- http://www.free.lp.se/fish/

FSH -- Fast SSH remote command execution
- FSH is an extension to ssh (on UNIX only) that permits sending multiple commands to the remote host through one SSH tunnel.
- http://www.lysator.liu.se/fsh/