HexChat - HexChat is a fork of XChat with bug fixes and new features.
mIRC - mIRC: Internet Relay Chat client
irssi - Irssi is a terminal based IRC client for UNIX systems.
Bidbar - Save and run Terminal commands from the Mac menu bar
Quassel IRC - Quassel IRC is a modern, cross-platform, distributed IRC client based on the Qt4 framework.
Hyper - Extensible, cross-platform terminal built on open web standards.