Common Lisp, because that's what I am learning right now.

Rust, because I finally made it from beginner to intermediate level (at least I think).

https://flix.dev/ looks very cool.

Also, recently someone posted this here on HN: https://github.com/coalton-lang/coalton

It's a statically-typed, functional language embedded in Lisp, with many of the FP goodies.