Several years ago I wrote up this post on pumps. There likely is a wider variety of pumps now that are as good as these, but these ones I looked at then are my favorite pumps to carry on a bike to this day.
https://www.bikeforums.net/touring/1...l#post18521373
Now that I have several more years of experience with these pumps, I will point out that have disassembled them to clean dust out from the innards a few times due to too much gravel riding. If you are doing months of touring, keeping a pump in a pannier might not be a bad idea if you are in a dusty environment.
A friend of mine carries his Lezyne pump upside down on the frame, he says that too much water collected in his pump with it upright.