I've been using a now discontinued multi-tool for many years, called the
Topeak toolbar.
It's a brilliant design:
1. Very small and lightweight, so it fits into even the smallest saddle bag (1/4 inch ruled paper):
2. Rounded edges, so there's no chance it will puncture a spare tube.
3. Thin but strong aluminum tire levers that slide out of slots on the side of the body.
4. A tool bit caddy inside the body that stores up to 5 bits of your choice.
5. Bits drop into the swivel head and are held in place with a magnet. Use it as a screwdriver for tight spaces.
6. Or swivel the head 90º to make it a right angle driver.
I can think of a couple of things that would make it better:
1. A detent on the swivel to help it stay in screwdriver or 90º position.
2. A ratchet mechanism on the swivel.
This tool has gotten me and others back on the road again many times.