I have an MBA and the career path I am on may require a PhD. I have no remaining GI Bill. Are there any programs available to assist me?

You can look up to see if your state of residence during your active duty years has any kind of grants. For example, Illinois has the Illinois Veterans Grant which authorizes any Illinois Veteran (AD, USAR, ARNG) to attend 120 hours of college (any level) at any public school. Other states have similar programs, though not all do.

Yes there is.

https://benefits.va.gov/gibill/fgib/stem.asp

From time to time the VA offers GI Bill supplimental programs, so check with them. Also, of course check with your current employer on tuition reimbursement. If your current employer does not offer it but another employer in your same field does then switch employers. Some employers (very rare) have cooperative agreements with some University programs in which you are also granted time off work to attend class. I have seen it in some circumstances. In other cases you can negotiate Flex Time to attend school with your boss. Most employers want to see you advance your education. Usually to Masters but some will support to PHd (General Motors supports to PHd in some cases). I have hopped to a different employer due to benefits. Now I have everything including pension and at a great employer.