Thought this might be of interest. Prop Store is hosting a movie poster art auction in a couple of weeks.
https://uk.propstoreauction.com/view-au ... 45/?page=1
These guys are known for their movie memorabilia auctions and sales, but they recently moved into movie posters. There are a bunch of interesting Mondo and Mondo-adjacent lots in here, including a ton of cool stuff from the Castro theater. Thought there may be some deals to be had.