It's also worth pointing out that all sorts of realistic history has all sorts of random stuff being carried by combatants. Organised raiding parties that are returning will be carrying loads of valuable odds and ends. Stories abound of the stuff that was initially being carried on the retreat from Moscow for instance e.g. milking stools!

In the non-humanoid space you have nesting/crow like behaviour - i.e. "shiny" things, the most famous being dragons and gold. So it's entirely possible for whole classes of creatures to generically carry certain things.