I don't know about other lisps, but Clojure has namespaces and that's good enough for me. So you can type "(foobar/" and get a list of functions in the foobar namespace.

Janet kind of has this too: if you import a module with (import foo), all the imported bindings will be prefixed with foo/. Also, this can be avoided by writing (use foo) instead.

Common Lisp also has namespaces, you can type '(asdf:' and get the functions ASDF provides.