SMM++ Mud Client is a mud client with extended and unique features. SMM++ features a highly customizable user interface (labels, buttons, and menus), unique and powerful mapping capabilities. Powerful scripting, even classes!
The Grendel Project
The Grendel Project is a modularized mud server: most functionality has been placed inside seperate modules which can be loaded/unloaded at will.
TinTin++ is a mud client that runs in console mode. TinTin++ should run on any unix/linux system (BSD, SuSe, Slackware, Debian, Mandrake, to name a few) and emulators, such as Cygwin for windows.
TinyFugue, aka "tf", is a flexible, screen-oriented MUD client, for use with any type of MUD. Features include: text terminal UI, with separate panes for user input and server output, a powerful scripting language, perl-compatible regular expressions, locale support, user-defined keybindings, and more.
TinyMUSH 3 is a descendant of the TinyMUD server, and thus supports multi-user communication in a text-based "virtual world" format, via TCP/IP connections (presumably, but not necessarily, Internet connections). The end result looks much like text adventures games of the mid-1980s. Though its simplest application is as a chat server, TinyMUSH 3 is intended to have the flexibility and power to support highly complex roleplaying environments.
TinyMUX is a text-based game server in the MUSH family. It is a platform that allows several thousand players to connect to a single text-driven environment, and interact with each other and with the environment (which is maintained in a database). The rich programming environment can be used to build almost anything, limited only by the developer's imagination.
tkMOO-light is an advanced chat client suitable for use with muds and especially MOO systems. The client runs on UNIX, Windows and Macintosh platforms.
tnMUD is a modular MUD server written in C++. Its lightweight core can by easily extended by modules, which are loadable/unloadable at runtime. The tnMUD project aims to create a fast and full-featured MUD server.
Trebuchet Tk is a client program for connecting to TinyMUD style social MUD servers on the InterNet. This program is designed to be used with TinyMUD, TinyMUCK, TinyMUSH, MOO, and several other variants. It's probably not well designed for combat oriented MUDs like LPMUD and Diku, but it does support them.
UnsignedByte is a modern MUD server. It uses an SQLite3 database as its backend instead of text-files.
The (VME) Valhalla Mud Engine is a commercial mud (Multi User Dungeon) server.
Wolfshade is a MUD (Multi-User Dimension), completely written in C++, with an object-oriented model and open source code. It is complete with full ANSI color, thousands of rooms, 27 races, 13 classes, 300+ spells, moving maps, God-run quests, race wars, and much more.
Xpertmud is an extensible perl, python and ruby scriptable MUD client. It is based on Qt and KDE. There's a native Linux/KDE version as well as a native Windows/Win32 build. It supports multiple windows (which are scriptable), and you can use triggers, aliases or whatever you want on every bit of text that comes from or goes to the server. There's a stable and intuitive plugin API, so you can extend the client with Qt-based C++ code. A sample plugin for the btech MUX is included.