MacMudClients

Cantrip

[Cantrip] is a client for connecting to Multi-User Dungeons/Domains?/Dimensions?, otherwise known as MUDs. MUDs are, put simply, online multiplayer text-based adventure games.

Rapscallion

[Rapscallion] is a popular Macintosh client. I noticed that both the client and the source code have been released for "free" use in March 2005.

Savitar

[Savitar] is a software application designed to connect people using Macintosh computers to MUD/MUSH/MOO/MUVE servers. Savitar is available for both OS 9 and OS X. Last updated in April 2005.