OpenXP is a multi-protocol offline mail and news reader for the text console, supporting Internet email, Usenet, Fidonet, Zconnect, etc. It is based on CrossPoint (XP) by Peter Mandrella.
Parma Tosser is FTN echotosser for DOS, OS/2, Win32, Linux platforms.
FTN echomail tosser for a node.
EvilBoss is the packet of utilities written on Perl. It's designed for configure/control big FidoNet Node or Hub.
Fidonet Technology Network (FTN) Client with integrated mail reader, tosser and scanner. Runs on Linux, in text mode. (console or remote) No active development has taken place since 2000, but it might be reopened in the future.