1. LED torches, about the size of a 10p piece but thicker, of course. I have two, one with a red LED and the other with a blue/white LED.
Red for cockpit work, blue/white for checking things eg pre-flight or seeing whether the ice on the wings is thick enough to switch the boots on.
2. Jepp. CR5 whiz wheel. Only 3.75" diameter & fits in almost any pocket. None of this clunky slide type computers for me.
3. A watch with world timezones, analogue face & whiz wheel. The bezel is great for currency conversions. Set & leave the rate when I arrive then no more calculations to work out what I'm paying.