All free lists are now per-interpreter! See Modules/gcmodule.c:

static void
clear_freelists(PyThreadState *tstate)
{
    _PyFrame_ClearFreeList(tstate);
    _PyTuple_ClearFreeList(tstate);
    _PyFloat_ClearFreeList(tstate);
    _PyList_ClearFreeList(tstate);
    _PyDict_ClearFreeList(tstate);
    _PyAsyncGen_ClearFreeLists(tstate);
    _PyContext_ClearFreeList(tstate);
}

I'm still working on the Unicode caches.