Does a standard implementation of a Circular List exist for C++?

If you want something looking like an iterator you can roll your own, looking something like

template <class baseIter>
class circularIterator {
    private:
        baseIter cur;
        baseIter begin;
        baseIter end;
    public:
        circularIterator(baseIter b, baseIter e, baseIter c=b)
            :cur(i), begin(b), end(e) {}
        baseIter & operator ++(void) {++cur; if(cur == end) {cur = begin;}}
};

(Other iterator operations left as exercise to reader).

There's no standard circular list.

However, there is a circular buffer in Boost, which might be helpful.

If you don't need anything fancy, you might consider just using a vector and accessing the elements with an index. You can just mod your index with the size of the vector to achieve much the same thing as a circular list.