PUBG is the original Battle Royal, if you discount the iconic film.  So it makes sense that it must have stocked a lot of cosmetics by now.  PUBG has many different cosmetics, but the ones that really stand out to the players are full skins and outfits.  You can customize pretty much everything in the game, so it's a lot more modular than games like Fortnite or Apex Legends where one item covers your entire look.  PUBG is more based around optimizing each section like an avatar creator.  However within this more complex system, there are actually some rare PUBG skins and cosmetics.  These singles differ between rare PUBG outfits and cosmetics that are part of an organization

  Ever since PUBG added looting, the rarity of some organizations skyrocketed.  These fortune-based efforts to obtain certain cosmetics have artificially created a shortage of certain things in the game.  The outfits you have to take from these boxes are definitely something rare in the game.  However, some rare PUBG skins were also obtainable as a general cosmetic purchase or as a bonus.  These are the outfits that will really make you stand out in PUBG.