I don't think there's such a thing. I know for a lot of PM&R programs they'll say pre-lim years in IM, Surgery, Transitional Year, Pediatrics, FM, OB-Gyn, and sometimes Psych are all accepted. And I think PM&R is more flexible on that than most other advanced specialties. But the only true pre-lim years out there are in IM, Surgery, and TY's. Anything else just means that you could match into Peds or FM, and then if you decide to change and reapply to PM&R, your first year of that residency counts as a prelim year.