Archivist Maps and Explorer Backpacks in Shadow of the Tomb Raider will reveal all other Collectible Locations on the map! They are very helpful when going for 100% game completion. Then all other collectibles get marked on the map (except Tombs and Challenges). The maps and backpacks themselves don't count towards 100% completion, they just make your life easier with the actual collectible locations.

[ Register or Signin to view external links. ] Archivist Map: Reveals all Relics, Murals, Documents Monoliths on the map.

[ Register or Signin to view external links. ] Explorer Backpack: Reveals all Crypts, Treasure Chests, and Survival Caches on the map.

None of these items nor the collectibles are missable. You can get everything after the story in free-roam. Base Camps for fast travel back to the first map (Cozumel) also unlock after the story.