mIRC - mIRC: Internet Relay Chat client
Kiwi IRC - A hand-crafted IRC client that you can enjoy. Designed to be used easily and freely.
HexChat - HexChat is a fork of XChat with bug fixes and new features.
Bidbar - Save and run Terminal commands from the Mac menu bar
irssi - Irssi is a terminal based IRC client for UNIX systems.
Hyper - Extensible, cross-platform terminal built on open web standards.