Raw lisp is obviously very easy, not sure about the various schemes.
OCaml, the whole SML family are easy to parse (just an LR grammar that is easy to copy). I think Rust is the same.
IIRC, Java is LL(k), so very easy.
C is not LR(1) for annoying reasons (typedef). Same for Go, IIRC. Otherwise, it's okayish. Javascript has this inane "optional semicolon" thing, which probably makes it annoying.
C++ is probably the most insane thing to parse. And then, there is bash[1].