- ChatZilla (open source) — ChatZilla is an IRC client extension for most Mozilla-based browsers (Mozilla App Suite, Mozilla Firefox, etc).
- Colloquy (open source) — Colloquy is a popular IRC client for Mac OS X, with a great deal of features including emoticons, tabbed chatting, and custom themes.
- Conversation (freeware) — Conversation is a great IRC client for Mac OS X. It has excellent AppleScript support and is very user-friendly.
- Pidgin (Formerly known as Gaim, open source) — Pidgin can connect to multiple chat networks (including AIM, ICQ, IRC, MSN Messenger, Yahoo! Messenger). It also works on many different operating systems (Windows, Linux, Mac, etc) although installation in some operating systems may not be straightforward.
- IceChat (commercial) — IceChat is a Windows IRC client written in Visual Basic. It provides some features other IRC clients do not, such as emoticons and an official support channel.
- mIRC (commercial) — mIRC is one of the most popular IRC clients with a lot of great features.
- Trillian (commercial) — Trillian connects to multiple chat networks (including AIM, ICQ, IRC, MSN Messenger, Yahoo! Messenger). It has more features than Gaim, but only works in Windows.
- X-Chat (open source) — X-Chat is a great multiplatform IRC client, completely free for Linux and Mac OS X, shareware for Windows but you can still download the source and compile it yourself, or get an unofficial version.