You might find this article interesting, although the company behind the article only works directly with doctors, though in most states consumers can order these directly through third party sites like walkinlabs - The 5 Most Commonly Ordered Functional Medicine Lab Tests (rupahealth.com).
This is a great list. I actually run four of the five of these in my practice . Even if someone is able to get access to these tests directly, interpretation is often non-trivial. And, deciding how to deal with what is found requires an experienced practitioner. This is why it's important to get these through a practitioner. Taking the wrong action could make things worse.