Quassel IRC is a modern, cross-platform, distributed IRC client, meaning that one or more clients can attach to and detach from a central core, much like the popular combination of screen and a text-based IRC client, but graphical. In addition to this unique feature, it aims to be a comfortable chatting program.
ngIRCd is a portable IRC daemon written from scratch. It is easy to configure, supports server links (even with original ircds) and runs on hosts with changing IP addresses (such as dial-in networks). Currently supported platforms are AIX, A/UX, Darwin/Mac OS X, FreeBSD, HP-UX, IRIX, Linux, NetBSD, SunOS/Solaris, and Windows with Cygwin.
BitchX is the premiere IRC (Internet Relay Chat) client. It originally was a modified version of the popular ircII client, and the features were eventually merged into the EPIC IRC client. The current development is aimed at merging the client back to a current branch of EPIC and bringing compatibility and stability back to the client, while bringing the features that are BitchX into a new client.
ircproxy is an Internet Relay Chat Proxy, which works as a layer between your IRC client and the IRC server. It features bouncer capability and has more features, flexibility, and configuration options than other tools. It also includes an option to use the system password list instead of requiring a separate password database.
dd_chat (formerly known as dd_ntalk-door) is a chat system derived from ntalk to be used with the DayDream BBS. The dd_chat client is a "door" program for the DayDream BBS that provides an easy-to-use chat client for the dd_chat server. Unlike the original ntalk client / server system, dd_chat implements several features from DayDream's libdd as well as an extended command set. It integrates seamlessly into DayDream. It features private conversation, checking for remaining BBS online time, chat idle timeouts (five minutes, except when in "away" mode), support for an ANSI logo and ANSI help screens from DayDream's "display" directory, and updating user status in DayDream.
dircproxy is an IRC proxy server ("bouncer") designed for people who use IRC from lots of different workstations or clients, but wish to remain connected and see what they missed while they were away. You connect to IRC through dircproxy, and it keeps you connected to the server, even after you detach your client from it. While you're detached, it logs channel and private messages as well as important events, and when you reattach it'll download those logs to you using ordinary IRC protocol.