Per https://support.plex.tv/hc/en-us/articles/200220677 (near the bottom), and as explained further here: https://forums.plex.tv/discussion/163035/how-do-extras-work, movie “extras” can be tracked, searched, and presented along with the main movie by placing the extras media files into specially- & precisely-named folders located within the main movie’s folder.
Currently these subfolders include:
- Behind The Scenes
- Deleted Scenes
- Featurettes
- Interviews
- Scenes
- Shorts
- Trailers
I suggest two others:
- “Extras” - helpful as a generic dumping ground, and for otherwise-uncategorized related media
- “Alternate Versions” - for director’s cuts, despecialized editions, fan edits, alternate endings, etc.
A related suggestion is to allow for special media to be placed in folders (within the main movie folder) with user-chosen folder names.
For instance, for some movies, it could be good to collect “Alternate Versions” of the main movie in a separate folder, containing only and all of the main movie’s alternate versions. These alternate versions would show up in Plex with this name (i.e., “Alternate Versions”).
The same may apply to “DVD Extras”, or to “Music Videos”, or “Making of” or “Ultimate Edition”, for example, or any other user-desired grouping of Extras content.
One way to accomplish this–just a possibility, not suggesting it be what Plex developers choose–would be to have Plex consider any subfolder (in the main movie folder) that begins with an underscore as a special-content folder.
Thus, for a subfolder named “_Comic Cartoons”, Plex would show the content, along with the main movie, as Extras, grouped together and categorized/named as “Comic Cartoons”.