Scheme, Common Lisp, Haskell, [edit] Smalltalk, probably more obscure ones...
Also, Erlang, Rust, and Clojure, though those have been rumored to be employable, so no longer get as much of the filter as you get when it was just people caring strongly enough to want to use a particular language despite the unemployability.
Whether that caring happened because of skill (to identify something good), or skill happened because of caring (to invest the time in exploration and thinking and practice), these communities seem to get more than their share of great programmers.
And so you know where to look for them, and you have a reason that they might want to talk to you.
Also, Erlang, Rust, and Clojure, though those have been rumored to be employable, so no longer get as much of the filter as you get when it was just people caring strongly enough to want to use a particular language despite the unemployability.
Whether that caring happened because of skill (to identify something good), or skill happened because of caring (to invest the time in exploration and thinking and practice), these communities seem to get more than their share of great programmers.
And so you know where to look for them, and you have a reason that they might want to talk to you.