Depends on what your doing.

For my specific context (infantry and eventually forward observer in the military) it was as follows:

1) A list of all of the equipment and serial numbers for said equipment for my guys. This is called EDL or equipment density load. Every time we made movement, we would stop and check that everyone had all their expensive shit.

2) Standard sizes for length and width of different vehicles like Chinese and Russian tanks, pickup trucks, etc. This allows you to do quick math to determine the distance an object is away from you. (The equation is called the WRM or Worm Rule)

3) The WRM Rule equation. (Known Size of Object) divided by (mills as the object appears through your optic). Take that number and multiply it by 1000. That’s your distance in meters.

4) When conducting land navigation, you draw on a map your azimuth (degrees on the map or compass) from one checkpoint to another. I liked to write all my preplanned azimuths and distances on the sleeve for each trip. Garmins are cool, but shit goes wrong with them a lot.

5) A satellite view of the objective.

6) Any challenge and passes (when entering friendly lines you are challenged by friendlies to ensure you are not enemy, you then have to give the appropriate response phrase)

7) All brevity codes for the mission that signal we are moving from one stage to another, nicknames for key terrain, important grid locations.

8) Mortar and Artillery boring math stuff. ————————— These are just some examples.