Martian's MOO Extensions
- Built-in functions replacing various often used core verbs and providing an interface to QDBM and ZLib functions.
- http://www.martian.cx/Code/MOO/

File Utility Package
- Provides access to files from MOO code. FUP also provides file searching capabilities and the ability to run external programs from MOO code.
- ftp://bioinformatics.weizmann.ac.il/pub/software/MOOsupport/FUP/

File I/O
- Adds several wizard-only functions for manipulating files from inside the MOO, only allowing access to a directory under the server's current directory.
- http://thwartedefforts.org/software/fileio/

DB Backup Script
- This set of scripts automatically back up the MOO's checkpoint dbs whenever the server completes a checkpoint.
- http://www.xythian.com/moo/dbbackup.html

WinMOO
- Unofficial server that runs on Windows.
- http://www.stanford.edu/~cunkel/WinMOO/

MacGoesMOO 1.0b11
- An unofficial server to run a MOO on MacOS.
- http://www.fringenet.net/MOO/MGM1.0b11PPC.sit

SMUD - SOAP Driven Multi User Dungeon
- A multi-user dungeon loosely based on the "Dungeons & Dragons" world. The most important aspect of this server is that it accepts client connections via SOAP/XML envelopes.
- http://sourceforge.net/projects/smud

Tinymush 3
- Descendant of TinyMUD, supports multi-user communications in a text-based virtual world format.
- http://tinymush.sourceforge.net/

EmberMUD
- Flexible open-source MUD engine, capable of supporting almost any role-playing setting.
- http://sourceforge.net/projects/embermud

The MUD32 Project
- Notes on a Windows based Mud server.
- http://www.Jaruzel.com/mud

Bluemud
- Based on Varium project. Features documentation, research and project details.
- http://bluemud.sourceforge.net/

[rec.games.mud]: FAQ #4/4: Servers at a glance
- Detailed information about mud server types.
- http://www.mudconnect.com/mudfaq/mudfaq-p4.html

KoalaMUD
- Koala is a highly-distributed IP6/IP4 MUD server. It allows for very large game worlds to be distributed between multiple machines in a manner transparent to players.
- http://koalamud.sourceforge.net/index.php3

CoolMUD Server
- CoolMUD is an object-oriented, disk-based MUD server originally written by the creator of MOO. It has support for distributed processing. This version features some bug fixes in the server and improved in-database code.
- http://www.digitalkingdom.org/~rlpowell/coolmud/index.html

CGMUD
- Graphical MUD system ported from AmigaMUD. Has a graphical MUD client written in Java and an efficient server written in C. CGMUD is not derived from any other MUD and has no licensing restrictions.
- http://www.graysage.com/cg/MUD/CGMud/index.html

Kanga.nu MUD Server FTP Archive
- Repository of MUD servers containing many old servers of historical interest, as well as new ones.
- ftp://ftp.kanga.nu/pub/MUD/Servers/

New MUD Code-bases
- Catalog of new and original MUD servers for different platforms and programming languages. Includes short descriptions and links to the project web pages and their authors.
- http://www.andreasen.org/newmud/

Valhalla Mud Engine
- MUD engine by the original writers of the DIKU MUD server. Unlike DIKU, VME is available under a business license that allows commercial exploitation.
- http://www.valhalla.com/vmeinf/index1.html

The AIME Project
- An open-source MUD engine, designed to provide as much flexibility as possible to the designer creating the online world.
- http://aime.sourceforge.net

Muq
- Ambitious distributed MUD server with a long list of features. One of the main aims of the project is to construct non-proprietary online communities based on free software.
- http://www.muq.org/

The Grendel Project
- A MUD server for Win32 written in Delphi 5. Features include multi-threaded design, copy-over procedure and IPv6 support.
- http://www.grendelproject.nl/

DUMB MUD
- The 'Diabolically Uncrashable MUD Builder' project aims to provide a server that is first and foremost stable and reliable. The DUMB language is a dialect of Lisp.
- http://jlmud.sourceforge.net/

16K MUD Competition Results
- Results of a competition to write the best possible MUD server in under 16 kilobytes.
- http://www.andreasen.org/16k.shtml

Momoko
- An open source, modular, extensible platform for building multi-user environment. Momoko transparantly distributes objects over multiple servers and supports several scripting languages. Written in Java.
- http://momoko.sourceforge.net/

FTP.GAME.ORG Mud Archive
- A directory of MUD server sources and other related files available for FTP, organized by server type.
- http://www.game.org/ftpsite/