OnlineRoleplay.Com!
- Directory of role playing mud sites and resources.
- http://www.onlineroleplay.com/Roleplay_Guides_And_Resources/

Rachel's Super MOO List
- List of MOO's with descriptions of each. Note: This site is no longer maintained, and many listings are unavailable.
- http://cinemaspace.berkeley.edu/~rachel/moolist/

MOOring
- Contains links to information sites.
- http://mooring.reinyday.com/

Echo Duet MOO List
- Collection of links to active MOO's, the list is sorted by category or alphabetically and includes a description. It also features a suggestion form for users to add to the directory.
- http://moo.echoduet.net/

Maelstrom: MU*/Talker Listing A to Z
- Ratings, user counts, and an interface for user changes.
- http://maelstrom.areth.org/mud/

Lysators MUDs
- Listing of MUDs hosted at Lysator.
- http://www.lysator.liu.se/mud/main.html

MudNow
- A new listing site where one can place their own listings and reviews of muds. Also has resources for the mud building.
- http://www.mudnow.8m.com/

Top Mud Sites
- MUDs ranked according to visitor votes.
- http://www.topmudsites.com/

Rhal's Furry MU*s Connector
- List of online multi-person shared environments (MUCKs, MUSHes) featuring anthropomorphics.
- http://www.tigerden.com/~infopage/muck/

Deutsche MUD-Liste
- List of MUDs in Germany (written in English and German).
- http://www.mud.de/DML/