Sniper Elite 4 has a massive 322 collectibles to find, across the following categories:
No collectibles are missable, since you can replay any mission, and you don’t need to grab a collectible again if you die. Most are either hidden or dropped by enemies, but the Deadeye Targets are eagle targets you must shoot to collect.
Every mission has collectibles, including the “Compound” and “Railyard” co-op missions.
Follow the videos below to find the locations of every collectible in each mission.
There are additional collectibles to be found in the Target Führer DLC.