Parker pen refill. Fits in your wallet and you can write with it. Who needs Swisscards???

On that note, some sort of paper sheet. It can have words on it or whatever, it's still good for writing, fire starting and (mainly) wiping your aesthetically challenged parts.

Rubber bands. Keep wires and lanyards neat and organized, plus could one day save your life. Somehow. Probably.

Snack. Use something physically tough and full of calories - somebody here suggested halvah once and it worked great for me. I use 20 gramm portions.