rxvt-unicode is a clone of the well known terminal emulator rxvt, modified to store text in Unicode and to use locale-correct input and output. It also supports mixing multiple fonts at the same time, including Xft fonts, real transparency, and an optional embedded Perl interpreter that allows you to extend your terminal easily.
The mgetty package contains an intelligent getty for allowing logins over a serial line (such as through a modem) and receiving incoming faxes. The companion program sendfax is used for sending faxes from the commandline or from other applications. The third main component is vgetty/vm which can be used with a voice-capable modem to implement an answering machine, a voice menu system, and similar things.
SMSTerm is an application that uses the ICQ2000 protocol to present you a shell on your mobile phone which allows you to interact with your computer from any mobile on a GSM network. It runs a shell on a pty, and allows you to directly send commands to the shell through SMS. Minimal authentication is done over SMS before spawning a shell and offering it to the user on the mobile phone. It is very useful for remote administration tasks, or checking out the status of the network, or just to run some small chores on your system while you are away. It uses Expect.pm in the background. SMSTerm also includes a script to send SMS through the ICQ network from the command line to any GSM mobile, and also includes a PHP script to set up a Web->SMS gateway.
Mail2sh makes it possible to carry out shell commands by email. Email is sent to a particular user on your host and the commands will be carried out if the user and password given matches ones in /etc/passwd. Commands are executed with the user's privileges, and combined with a PGP module ensures a certain level of security for use. Note that the system is not natively encrypted, so use of an encryption mechanism is highly recommended for security reasons.
NOTE is a small console program that allows you to manage notes similar to programs like "knotes" from the command line. It supports different database backends for storage, and includes a DBI-based MySQL module and another module that uses a binary file for storage and a DBM module.
MudMagic Mud Client is a GTK/GNOME multi-platform MUD client. It provides aliases, triggers, multiple connections, plugins, MCCP, ZMP, MSP, tabbed sessions, ANSI color, and a game list that can be updated from mudmagic.com. It is configurable on a per-session basis. Plugins include an automapper, database, and note pad.
mcl is a MUD client running in a Virtual Console under Linux or using standard TTY routines under any other UNIX. Embedded Perl or Python offer very high tweakability. Other features include huge scrollback, a stable input line with the MUD prompt, Perl regexps for actions and substitutions.
KildClient is a MUD client written with the GTK+ windowing toolkit. It supports many common features of other clients, such as triggers, gags, aliases, macros, timers, and much more. But its main feature is the built-in Perl interpreter. At any moment, the user can execute Perl statements and functions to do things much more powerful than simply sending text the the MUD. Perl statements can also be run, for example, as the action of a trigger, allowing you to do complex things.