I guess basically for anything. From AutoCAD (https://en.wikipedia.org/wiki/AutoLISP) extensions to grammar checking engines (https://www.grammarly.com/blog/engineering/running-lisp-in-p...)?

If you count Clojure and ClojureScript as kind of Lisp then for instance our whole product (https://orgpad.com) backend and frontend is written in it. Of course there is also some SQL, CSS etc. in between but basically all the meat is in CLJ or CLJS.