Does Swift have a large community beyond iOS apps? Last I used it was years ago, right after it was introduced by Apple. I'm curious if it has found growth in other areas.

Not really atm. There is a small community around server-side-swift which did some impressive work so far, most interesting project is IMO the Vapor Framework [1], but at least outside the Apple Dev community they didn’t get much attention so far. For general system programming, which would be also possible with swift, Rust seems currently a lot more popular.

[1]: https://vapor.codes

For people not familiar, Vapor is close to releasing version 3.0, using https://github.com/apple/swift-nio. I've heard rumors that the performance is really good, but I haven't ran anything personally.