This is all the modes plus Gun Game and Infected are included in the bonus playlists.
Supply drops are similar to CSGO cases as you get a weapon drop with a fixed camo and locked attachments. Each weapon is categorized as either Professional, Elite or Unlisted and have varying stats and attachments. You also get cosmetic items such as exo suits, bottoms and footware and helmets with camo too. There are about 350 different weapon combinations available to be unlocked as well as the standard weapons with customisable attachments and camo. It doesn't appear that the items you receive from supply drops are for trading which is a bit of a missed opportunity.