When on foot, backpacking which is about all we ever do there are several tools that are essential for me. This is subjective of course and will not apply for everyone.
I have broken enough of those plastic trowels so when I found a Mont Bell Scoop I scooped it up, never been able to damage it.
As far as edged tools go, in recent times and in fact just last week during a backcountry wilderness foray I have lived with the bottom two in this image;
Middle is the paring knife that does all the culinary work. We actually cook when out there, at least for dinner we do more than just boil. It cuts up zucchini, carrots and slices the shallots that go in our home made dry dinner mixes. We find if we eat some fresh veggies that our endurance lasts a lot longer over the end portion of the backpack trip. It also carved up a pre-cooked chicken I got at a market on the way home.
The bottom tool, the Leatherman Charge AL is a tool that I will use for the can opener, diamond file, small scissors and the blades at various times over a trip. The pliers have extracted some wicked cactus spines out of my hide as well as girlfriend and my dog.
We do up to five boils a day on the stove, one for morning tea or coffee, again for tea at lunch followed by soup. For dinner to cook our main meal and maybe chocolate pudding followed by some peppermint tea in the dark while watching the stars. The Swedish firesteel has always fired up the stove every time in any weather. Upper left corner;
Another essential is my Surefire Saint Minimus headlamp that dials up to a very bright beam for those times one needs a momentary blast of intense light, down to medium intensity when doing most foot travel in the dark and way down to very low for reading or close work around camp.
If I were to travel through a different country than the desert or had special concerns for a particular trip, I'd add what seemed a good idea at the time.