If you can't find some directly for Parse RecDescent, try looking for BNF notational grammars, the syntax is not quite the same, but they can be (mostly) easily converted.
Googling for '+BNF +"C++"' turns up this for example.

C.

In reply to Re: Available RecDescent Grammars? by castaway
in thread Available RecDescent Grammars? by kelan

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