Start with some of the indie productions rather than the majors. Heck some of the trained composers like Jerry Goldsmith would hire others to orchestrate his scores like Arthur Morton because Goldsmith found orchestration tedious and time consuming & because he trusted Arthur’s sensibility as an arranger as it matched Goldsmith’s own and he didn’t want to always take the time to essentially translate his scores due to multi-le commitments, time, etc. Morton also worked with J0hn Williams, etc. He also wrote music but primarily worked as a music orchestrator or arranger throughout his career going back to the 1930’s. When John Williams was on a tight schedule for “Jaws 2” for example, as I recall, Goldsmith recommended him to Williams.