HexChat is an open source, feature-rich, multi-network IRC client based on XChat. It offers a wide range of features, including Python/Perl scripting, spellcheck, proxies, SASL, DCC support. With an easy to use interface, it offers a great method of chatting online.
Halloy is an open-source IRC client written in Rust, with the Iced GUI library. It aims to provide a simple and fast client for Mac, Windows, and Linux platforms.