Freenode used to be one of the biggest networks in the past decade or so, but a few years ago, after a hostile takeover it went to shite, so most people have moved on to Libera Chat. Unfortunately IRC in general is a lot less quieter and lot more fragmented these days - with the more privacy-oriented folks having moved on to Matrix, the more gaming-oriented folks moved on to Discord, and usually niche, or old school open-source stuff is now what remains (most of them on Libera).