mIRC
The classic Windows IRC client with scripting support. Shareware but very popular.
⬇ Download mIRC
AdiIRC
A free, modern IRC client for Windows with themes, scripting, and multi-server support.
⬇ Download AdiIRC
HexChat
An open-source, cross-platform IRC client for Windows and Linux. Based on XChat but actively maintained.
⬇ Download HexChat
2pac Legacy Script
An ultimate mIRC script with Channel Protection and Self Protection Addons! - By |2|pac
⬇ Download 2pac Script
psyBNC
A lightweight IRC bouncer for staying connected 24/7, popular on Linux servers.
⬇ Download psyBNC
Eggdrop
The oldest and most powerful IRC bot, highly customizable with Tcl scripting.
⬇ Download Eggdrop