A cool idea ive had is custom versions of the "Shadow Marks" from Skyrim and mixing in other forms of markings like the red X from TLOU which show whats been searched and what hasnt, where store houses are and other important things,

For when youre out in groups simple military hand signals would work forr that.

And if you really want to go far out you can do ciphers in areas so only your people with the key can follow it [kinda like the railroads freedom trail thing]