There are a lot of movies from Local library that hasn't any trailer available due to the current integration with only one provider.
Would be awesome to integrate with more trailers providers such as Youtube, imdb, etc
According to the fine print on their home pages, neither IMDb nor YouTube own the licenses for those trailers. They’re merely allowed to host them from the license owners.
There’s been a lengthy discussion in the past about this and what it means. Long story short: while it might be ok for you as a private person to use those trailers, it’s not ok for Plex as a company. They do have to pay license fees to provide those trailers (as they are); hence the link to a Plex Pass membership. Just scraping them from those other hosters isn’t possible.