Any Clojure clients for Lemmy?

I'm not aware of any. There was just a major API changes though, away from a websockets API and toward something I believe is fairly RESTful. Though I haven't studied the new API, I suspect you'll find it's reasonable to use with a generic rest client like https://github.com/RokLenarcic/clj-rest-client

Like I said, all speculative though, I haven't tried.