for folks looking for libraries: https://github.com/CodyReichert/awesome-cl/

(I don't know for popularity but my personal opinion is that CL is still unmatched: this level of interactive development + good debugging tools + excellent implementation that compiles to fast machine code + fast startup for binaries + self-contained binaries + stable yet improving language, implementations and ecosystem + connect from a running program + commercial vendors if you need + … such a unique and productive set)

(re. the type system: https://github.com/coalton-lang/coalton/ for a Haskell on top of CL now)