If you feel 'Special Feature's are adequately covered by the existing list, please enlighten me on how you deal with them.
I have MC setup to handle my movie extras quite nicely.
I make a custom field called "Installment"
Typically the installment value is either "Disc 1" for full disc rips, or "Part 1" when ripped to mkv.
If there are multiple discs then there will be a Disc 1, Disc 2, etc.
If there are extras in an mkv rip the installments will look something like this:
Part 01 - Main Movie, Part 2 - Extras, Part 3 - Extras, etc.
All installments share the same movie name so they can all be scraped and have the same art.
I have just been stock piling my TV Show extras because I don't know what to do with them yet.
Maybe use season 3.1 for season 3 extras?
Or maybe give them episode numbers in the 100 range?
I will have some system in place by new year but am curious what others are doing.