I use one of these velcro and zip tied to the shoulder strap of my parachute.

https://www.ebay.com/c/1640576232

In it I have a space blanket, lighter, flashlight, knife, hook knife, old phone for 911 calls, pencil, tape, bandaids, rope, whistle, and matches in a water proof container.

The bag I linked above is just big enough to fit a fair amount o gear in while small enough to strap on the shoulder strap and not get in the way.