>Most of the languages you've listed are C-like and all of them have mostly similar syntax and function although the ecosystems are very differen

Fair-enough ... Within the category of C-like language, Dart is quite nice.

>Have you ever experienced larger applications written in completely different class of languages?

I have not. I have played around with lisp (scheme), prolog, Haskell, ML ... But for various reasons never used them professionally.