No there aren't. Admittedly, I'm a bit confused at the table, http://www.w3.org/TR/html5/syntax.html#named-character-references does in fact list entity names with and without semicolons. However, it is a parse error to not have a `;` after a named character reference.

That said, from reading http://www.w3.org/TR/html5/syntax.html#tokenizing-character-references, it turns out there's cases where the ampersand does not actually start a named character reference. Notably, there's a few characters that may follow the `&` that indicate it's not a character reference. And there's also some weird backwards-compatibility thing about parsing inside attributes, but I don't know of any html entity encoder/decoder routine that handles that.