CGoban 3 - Includes an editor for SGF go files and a client for the Kiseido Go Server. - http://www.gokgs.com/download.xhtml
GoKnot - GoKnot is an IGS telnet client and a Go player (playing locally against the GnuGo engine). - http://www.dybot.com/GoKnot/index.htm
The gGo client - gGo is a Go board, SGF editor, client for the Internet Go Server and an interface for playing with GNU Go. gGo is written in Java and available for Linux, OS X, OS/2 and Windows. - http://panda-igs.joyjoy.net/java/gGo/
Jago - Java-Client, Internet Go Server client, a Smart Go Format go game viewer and a point to point go player. - http://www.rene-grothmann.de/jago/
Java Go Client - A java plug-in to run Go against a server. - http://panda-igs.joyjoy.net/java/jgc15/index-e.html
TanGo - A freeware IGS and NNGS compatible Go client. - http://www.amourtan.com/
Complete Goban - Go program for Unix and X11. Local, internet or modem play, as well as .SGF-compatible record and replay. - http://www.igoweb.org/~wms/comp/cgoban/index.html
Xgospel - X-Window client for internet go servers. - http://gailly.net/xgospel/index.html