Great list guys.

Since my old steel launch rods seem to get dirty so I always carry some 3 in 1 oil and some 400 grit sandpaper. I give them a quick sanding and then clean the with a rag and the 3 in 1 oil.
Also:
Notebook & pens to record flight logs ( I am a nerd )
Cloths pins for that needed rod standoff
Extra balsa wood for repairs
2+ foot piece of 1/4 inch dowel
emery boards
multi tool
Extra shock cord

James Pierson
NAR# 77907