Well after thinking I had a nice little box started I have been severely put to shame by some of you guys.
So thanks for the suggestions.
They evolve over time - I could probably halve the number of items in my boxes if I chucked away the guff from older markers that I no longer own. For instance I still have a Stabilo Boss highlighter pen in my box - as they're the perfect size to hold apart Angel 1 eye covers when refitting them.....however I sold my A1 a couple of years ago and have no use for it at all now, but haven't bothered clearing out the redundant items.
One thing that is a god send is threadlock (Loctite) for use when re-assembling air fittings. You want the blue stuff, which can be disassembled with hand tools, not the red (colours vary - not all blue Loctite is good and not all red is bad - read the labels) stud locker which needs a blowtorch to remove. Usually comes in small squeezy tubes, however they have a tendency to dry out - Loctite also sell it in 'Pritt Stick' format, which is great and never dries out.