There are a few fairly wide-spread extensions to the set of "standard" BibTeX entry types and fields:
@webpage is fairly common, I think, and
eprint are fairly common fields. In some cases (eg,
url) it is obvious what should be in the field; in others (eg,
eprint) there's more than one natural convention for what the value should be.
I maintain the
urlbst package, and have contributed to the maintenance of a couple of other
.bst styles, so I've a fairly clear interest in consistency, here.
I suspect that the answer is "no" (I can't find one now, and I've never in the last couple of decades become aware of such a thing), and to that end I've called for some consensus-building, but if such a repository or effort already exists, I'd rather join in rather than create something anew.