Pidgin is a chat program which lets you log into accounts on multiple chat networks simultaneously. This means that you can be chatting with friends on XMPP and sitting in an IRC channel at the same time. Pidgin runs on Windows, Linux, and other UNIX-like operating systems.
Official site
deleted by creator
Matrix? It’s all XMPP. Has been available for many years and is pretty stable for small scale use.
deleted by creator