WisNeuro handled the response already, but as he said, IME = Independent Medical Evaluation. IME companies are third parties that essentially "match" their panel of experts (e.g., psychologists, physicians, audiologists, etc.) with companies seeking IMEs.
For criminal work, I've seen stuff come across my state listserv. Even if not interested in that specific work, reaching out to the people making those posts might be fruitful. And as you've already identified, state facility/government websites. Maybe tracking down names of other psychologists who do the criminal assessment work you're interested in, sending them an email/giving them a call, and offering to buy them lunch to talk about how they got into it.