I used to carry a Stein portable cassette removal tool, but it scratches the frame paint so I stopped carrying it.

For drive side spokes I carry a fiberspoke, which will take me far enough to reach the next bike shop. Even in the most remote part of the world, you will reach a bike shop after a few thousand miles.

I build my own wheels and have never broken a spoke on a wheel I built, so all of this is just hypothetical.