I collected these minor items here as a LG-secondary, and offload an overloaded sys2.

• [$=money can solve the problem]
• [$] spare foldable luggage bag
• [$] light foldable box for organizer — in hotels, or on empty neighbor seat
• flat water bottle
• [$] floss threader, inter-dental, double-floss with handle ,,,  too much time to kill
• food/drink boxes with tight lid — to prevent spill
• [$] clip-hook on knapsack
• [$] I have found the need for simple binders, string, hooks..
• .. strings needed for makeshift check-in luggage
• plastic bag hungable from my bottle .. good for acceptable rubbish, my food box, reading content..
• extra clear bags for various small items
• Singapore-style hangable coffee bag — needed on CE air planes.

— 3 types of charging cables .. increasingly, I need to cover the risk of no-charging for any of my devices [mlphone / android / laptop]. In most place I can buy a USB charging cable, so this item is a minor item. However, I tend to spend hours optimizing what to bring

• favor 3-head or 2-head cables
• spares .. keep some light-weight cables in luggage