Online auctions and or searches. Keep changing up the wording and/or put less specific search criteria to get more hits. I have bought that way. Took some time to wade through the info but it paid off in the end. A lot of the smaller places will put their stuff online, but put minimal wording on it, and it just won’t get the hits the bigger places do.
Also walked into a smaller dealership and a ‘rare’ item I wanted was right there in front of me. Actually had my mouth hanging open and was frozen in place for long enough I probably looked pretty silly.